Disaster recovery method, apparatus and system

Abstract

A disaster recovery method, apparatus and system, which can be applied in the technical field of storage. The method comprises: a first data center synchronously duplicating backup data to a second data center by means of a first synchronous duplication link; when a third data center is normal, the first data center asynchronously duplicating the backup data to the third data center by means of a first asynchronous duplication link; and when the third data center has a fault, the first data center asynchronously duplicating the backup data to a fourth data center by means of a second asynchronous duplication link, wherein the first data center and the second data center are both production centers and are located in a first area, and the third data center and the fourth data center are both disaster recovery centers and are located in a second area. The present application can achieve a step-by-step reduction in the disaster recovery performance of a disaster recovery performance, such that user demands are met to the greatest extent.

Description

Disaster recovery method, device and system

[0001] This application claims priority to the Chinese patent application with application number 202311298966.3 filed with the State Intellectual Property Office of China on October 9, 2023, and priority to the Chinese patent application with the invention name “A Disaster Recovery Method, Device and System”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of storage technology, and in particular to a disaster recovery method, device, and system. Background Art

[0003] Disaster recovery systems can provide business systems with an environment that can cope with various disasters, thereby ensuring the availability and data integrity of business systems. In existing disaster recovery systems, the first data center (DC1), serving as the production center for business operations, forms an active-active data center with DC2, a production center in the same region, to maintain real-time synchronization between DC1's data and DC2's. DC1 then relies on data transmission between DC2 and DC3, and between DC3 and DC4, to ensure consistency in business data between DC1 and the other three DCs. Specifically, asynchronous replication technology is used between DC2 and DC3, a disaster recovery center in another city, to maintain periodic synchronization between DC2's data and DC3's, thereby also maintaining periodic synchronization between DC1's data and DC3's data. DC3 transmits data in real time to DC4, a disaster recovery center in the same region, thereby also maintaining periodic synchronization between DC1's data and DC4's data. In summary, in a disaster recovery system configured in a "serial" fashion, when all four DCs are operating normally, DC1's data remains consistent with that of the other three DCs.

[0004] However, if data in production center DC2 is destroyed by an unavoidable natural disaster such as fire, flood, earthquake, or tsunami, or a man-made disaster such as computer crime, a computer virus, a power outage, network or communication failure, hardware or software errors, or human error, while production center DC1 can take over the business on DC2, DC1 becomes an "island" due to its inability to communicate with disaster recovery centers DC3 and DC4, thus losing the disaster recovery protection of disaster recovery centers DC3 and DC4. Therefore, if production center DC2 fails, the disaster recovery system's disaster recovery capacity will be reduced from four to one, causing a sharp decline in the system's disaster recovery performance.

[0005] Summary of the Invention

[0006] In order to solve the above technical problems, the present application provides a disaster recovery method, device and system, which can achieve a step-by-step reduction in the disaster recovery performance of the disaster recovery system, thereby meeting user demands to the greatest extent possible.

[0007] In a first aspect, a disaster recovery system is provided, comprising: a first data center, a second data center, a third data center, and a fourth data center. The first and second data centers are both production centers, and the third and fourth data centers are both disaster recovery centers. The first and second data centers are located in a first region, and the third and fourth data centers are located in a second region different from the first region. A first synchronous replication link exists between the first and second data centers, a second synchronous replication link exists between the third and fourth data centers, and a first asynchronous replication link exists between the first and third data centers. Furthermore, the disaster recovery system also includes one, two, or three of the following backup asynchronous replication links: a second asynchronous replication link exists between the first and fourth data centers, a third asynchronous replication link exists between the second and third data centers, and a fourth asynchronous replication link exists between the second and fourth data centers. The synchronous replication link is used to synchronously replicate backup data between the data centers at both ends of the synchronous replication link. The asynchronous replication link is used to asynchronously replicate backup data between the data centers at both ends of the asynchronous replication link. The backup asynchronous replication link is used to asynchronously replicate backup data between the first and second regions in the event of a failure in the first or third data center.

[0008] In the above solution, after establishing the first synchronous replication link, the second synchronous replication link, and the first asynchronous replication link, one, two, or three backup asynchronous replication links are established. This allows the data centers at both ends of the backup asynchronous replication link to directly transmit backup data, achieving synchronization of the backup data. This creates a disaster recovery protection relationship between the data centers at both ends of the backup asynchronous replication link. In the event of a failure in the first or third data center, the remaining three normally operating data centers can still synchronize backup data via the backup asynchronous replication links. Therefore, the disaster recovery system's disaster recovery scale is reduced from four to three, and disaster recovery performance decreases in a step-wise manner, maximizing user satisfaction.

[0009] In some possible implementations, the multiple backup asynchronous replication links serve as backup links for each other.

[0010] In the above solution, multiple backup asynchronous replication links serve as backup links for each other. Therefore, in the event of a failure between any two data centers—for example, if both fail simultaneously, or if one fails first and then the other fails after a period of normal operation—the disaster recovery system can still use the backup link to asynchronously replicate the backup data, thereby synchronizing the backup data of the remaining two normally operating data centers. This ensures that the disaster recovery system's disaster recovery capacity is reduced from four to two, resulting in a step-by-step decrease in disaster recovery performance. Alternatively, in the event of a sudden failure of any two asynchronous replication links, the disaster recovery system can still use the backup link to asynchronously replicate the backup data, thereby synchronizing the backup data of the four data centers, ensuring that the disaster recovery system's disaster recovery capacity remains at four.

[0011] In some possible implementations, the backup data is a snapshot or a log.

[0012] In some possible implementations, the first data center and the second data center are active-active data centers. The first data center and the second data center are configured to provide the same services and the same logical unit number (LUN) to the outside world, so that clients can access the first data center or the second data center through the LUN. In the event of a failure in the first data center or the second data center, client access is switched to the surviving data center through the LUN.

[0013] In the above solution, the first data center and the second data center form an active-active data center, so that the two data centers can carry services at the same time, with high compatibility and applicability, high resource utilization and good user experience.

[0014] In some possible implementations, the third and fourth data centers are active-active data centers. The third and fourth data centers provide the same services and the same logical unit numbers (LUNs) to the outside world, allowing clients to access the third or fourth data center through the LUNs. Furthermore, if the third or fourth data center fails, client access is switched to the surviving data center through the LUNs.

[0015] In the above solution, the third data center and the fourth data center form an active-active data center, so that the two data centers can carry services at the same time, with high compatibility and applicability, high resource utilization and good user experience.

[0016] In a second aspect, a disaster recovery method is provided, comprising: synchronously replicating backup data from a first data center to a second data center via a first synchronous replication link. Furthermore, when the third data center is operating normally, the first data center asynchronously replicates the backup data to the third data center via a first asynchronous replication link. In the event of a failure in the third data center, the first data center asynchronously replicates the backup data to a fourth data center via a second asynchronous replication link. The first and second data centers are both production centers, located in a first region, and the third and fourth data centers are both disaster recovery centers, located in a second region different from the first region.

[0017] In the above solution, the first data center synchronously replicates backup data to the second data center via the first synchronous replication link, ensuring real-time consistency between the backup data of the first and second data centers. When the third data center is operating normally, the first data center asynchronously replicates the backup data to the third data center via the first asynchronous replication link, ensuring consistency between the backup data of the first and third data centers. This achieves synchronization of backup data among the first, second, and third data centers. Furthermore, in the event of a failure in the third data center, the first data center can still send backup data to the fourth data center via the second asynchronous replication link, thereby synchronizing the backup data of the first and fourth data centers and establishing a disaster recovery relationship between the first and fourth data centers. With this disaster recovery relationship in place, if the second data center is operating normally, the disaster recovery system's disaster recovery capacity decreases from four to three, resulting in a step-wise decrease in disaster recovery performance. If the second data center also fails, the disaster recovery capacity decreases from four to two, with the same step-wise decrease in disaster recovery performance, thus maximizing user satisfaction.

[0018] In some possible implementations, the above method also includes: in the event of a failure of the first data center, the second data center asynchronously replicates the above backup data to the third data center via a third asynchronous replication link, or the second data center asynchronously replicates the above backup data to the fourth data center via a fourth asynchronous replication link.

[0019] In the above solution, if the first data center fails, the third data center can still receive backup data from the second data center via the third asynchronous replication link, thereby synchronizing the third data center's backup data with the second data center's backup data, thereby establishing a disaster recovery protection relationship between the second and third data centers. If the disaster recovery protection relationship between the second and third data centers exists, if the fourth data center operates normally, the disaster recovery system's disaster recovery capacity will be reduced from four to three, with a step-by-step reduction in disaster recovery performance. If the fourth data center also fails, the disaster recovery system's disaster recovery capacity will be reduced from four to two, with the same step-by-step reduction in disaster recovery performance, thus maximizing user satisfaction.

[0020] In some possible implementations, the backup data is a snapshot or a log.

[0021] In some possible implementations, the first data center and the second data center are active-active data centers. The first data center and the second data center provide the same services and the same logical unit number (LUN), allowing clients to access the first data center or the second data center through the LUN. In the event of a failure in the first data center or the second data center, client access is switched to the surviving data center through the LUN.

[0022] In some possible implementations, the first data center synchronously replicating the backup data to the second data center through the first synchronous replication link includes:

[0023] The first data center synchronously replicates the backup data and the data generated by the client accessing the first data center to the second data center through the first synchronous replication link.

[0024] In the above solution, in addition to synchronously replicating backup data, the first data center also synchronously replicates data generated by client access to the second data center, thereby enabling real-time synchronization of data between the first data center and the second data center.

[0025] In some possible implementations, the third and fourth data centers are active-active data centers. The third and fourth data centers provide the same services and the same logical unit number (LUN), allowing clients to access the third or fourth data center through the LUN. In the event of a failure in the third or fourth data center, client access is switched to the surviving data center through the LUN.

[0026] According to a third aspect, a disaster recovery device is provided, which is used as a first disaster recovery device, and includes: a synchronous replication module and an asynchronous replication module. The synchronous replication module is used to synchronously replicate backup data to the second disaster recovery device via a first synchronous replication link. The asynchronous replication module is used to asynchronously replicate the backup data to the third disaster recovery device via the first asynchronous replication link when the third disaster recovery device is normal. The asynchronous replication module is also used to asynchronously replicate the backup data to the fourth disaster recovery device via the second asynchronous replication link when a failure occurs in the third disaster recovery device. The first disaster recovery device and the second disaster recovery device are both production centers, the first disaster recovery device and the second disaster recovery device are located in a first area, the third disaster recovery device and the fourth disaster recovery device are both disaster recovery centers, and the third disaster recovery device and the fourth disaster recovery device are located in a second area different from the first area.

[0027] In some possible implementations, the backup data is a snapshot or a log.

[0028] In some possible implementations, the first disaster recovery device and the second disaster recovery device provide the same services and the same logical unit number LUN to the outside world, so that the client can access the first disaster recovery device or the second disaster recovery device through the LUN, and in the event of a failure of the first disaster recovery device or the second disaster recovery device, the client's access is switched to the disaster recovery device that has not failed through the LUN.

[0029] In some possible implementations, the synchronous replication module is specifically configured to synchronously replicate the backup data and data generated by the client accessing the first disaster recovery device to the second disaster recovery device via the first synchronous replication link.

[0030] In a fourth aspect, a storage server is provided, comprising a processor and a memory, wherein the memory is used to store instructions, and the processor is used to execute the instructions. When the processor executes the instructions, the method of any one of the second aspects is performed.

[0031] In a fifth aspect, a computer program product comprising instructions is provided, which, when executed by a computing device, causes the computing device to perform any method as described in the second aspect.

[0032] In a sixth aspect, a computer-readable storage medium is provided, comprising computer program instructions. When the computer program instructions are executed by a computing device, the computing device executes the method according to any one of the second aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0034] FIG1 is a schematic structural diagram of a disaster recovery system provided by the present application;

[0035] FIG2A is a schematic diagram of the structure of a disaster recovery system under a normal operating mechanism provided by the present application;

[0036] FIG2B is a schematic diagram of the structure of a disaster recovery system under another normal operating mechanism provided by the present application;

[0037] FIG2C is a schematic diagram of the structure of a disaster recovery system under another normal operating mechanism provided by the present application;

[0038] FIG2D is a schematic diagram of the structure of a disaster recovery system under another normal operating mechanism provided by the present application;

[0039] FIG3 is a flow chart of a data synchronization method provided by the present application;

[0040] FIG4A is a schematic diagram of an operation mechanism of a disaster recovery system provided by the present application under a failure of data center A;

[0041] FIG4B is a schematic diagram of the operating mechanism of another disaster recovery system provided by the present application when data center A fails;

[0042] FIG4C is a schematic diagram of the operation mechanism of a disaster recovery system provided by the present application under a failure of data center B;

[0043] FIG4D is a schematic diagram of an operating mechanism of a disaster recovery system provided by the present application under a failure of data center C;

[0044] FIG4E is a schematic diagram of the operating mechanism of another disaster recovery system provided by the present application under a failure of data center C;

[0045] FIG4F is a schematic diagram of an operating mechanism of a disaster recovery system provided by the present application under a failure of data center D;

[0046] FIG4G is a schematic diagram of the operation mechanism of a disaster recovery system provided by the present application under failure of data centers A and B;

[0047] FIG4H is a schematic diagram of the operation mechanism of a disaster recovery system provided by the present application under failure of data centers A and C;

[0048] FIG4I is a schematic diagram of the operation mechanism of a disaster recovery system provided by the present application under failure of data centers A and D;

[0049] FIG4J is a schematic diagram of the operation mechanism of a disaster recovery system provided by the present application under failure of data centers B and C;

[0050] FIG4K is a schematic diagram of the operation mechanism of a disaster recovery system provided by the present application under failure of data centers B and D;

[0051] FIG4L is a schematic diagram of the operation mechanism of a disaster recovery system provided by the present application under failure of data centers C and D;

[0052] FIG4M is a schematic diagram of the operation mechanism of a disaster recovery system provided by the present application under the failure of an asynchronous replication link between data centers A and C;

[0053] FIG4N is a schematic diagram of the operating mechanism of another disaster recovery system provided by the present application under the failure of the asynchronous replication link between data centers A and C;

[0054] FIG4O is a schematic diagram of the operating mechanism of another disaster recovery system provided by the present application under the failure of the asynchronous replication link between data centers A and C;

[0055] FIG5 is a flow chart of a disaster recovery method provided by the present application;

[0056] FIG5A is a flow chart of a method for implementing a preset disaster recovery solution in the event of a failure in data center A provided by the present application;

[0057] FIG5B is a flow chart of a method for implementing a preset disaster recovery solution in the event of a failure in data center C, as provided in the present application;

[0058] FIG5C is a flow chart of a preset disaster recovery solution provided by the present application when two data centers fail;

[0059] FIG5D is a flow chart of a preset disaster recovery solution provided by the present application when any asynchronous replication link fails;

[0060] FIG6 is a schematic structural diagram of a disaster recovery device provided by the present application;

[0061] FIG7 is a schematic diagram of the structure of a storage server provided in this application. DETAILED DESCRIPTION

[0062] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0063] In order to solve the problem of a drastic drop in the disaster recovery performance of the existing disaster recovery system due to a DC2 failure, the present application provides a disaster recovery method, device and system that can realize full interconnection of four data centers, so that there is a disaster recovery protection relationship between any two data centers, and can realize a step-by-step decrease in the disaster recovery performance of the disaster recovery system, thereby maximizing the satisfaction of user demands.

[0064] Refer to Figure 1, which is a structural diagram of a disaster recovery system provided by the present application. The disaster recovery system is used to provide an environment for the business system to cope with various disasters, ensuring the availability of the business system and the integrity of the business data. As shown in Figure 1, the disaster recovery system 10 includes four data centers, namely the first data center 11 (DC11), the second data center 12 (DC12), the third data center 13 (DC13) and the fourth data center 14 (DC14). Among them, DC11 and DC12 are both production centers, DC13 and DC14 are both disaster recovery centers, DC11 and DC12 are in the first area 151, DC13 and DC14 are in the second area 152, and the first area 151 and the second area 152 are different areas. Among them, the area is used to describe the geographical location relationship, which can be a country, province, city, etc. DC11 and DC12 are in the same area, so their geographical distance is closer, such as in the same city. DC11 and DC13 are in different areas, so their geographical distance is farther, such as in different cities.

[0065] In the disaster recovery system 10, DC11 and DC12 in the first area 151 form an active-active data center, so that the two data centers can carry services simultaneously, with high compatibility and applicability, high resource utilization, and good user experience. Specifically, when all four data centers are operating normally, DC11 and DC12 jointly carry the services of the first area 151. DC11 and DC12 provide the same logical unit number (LUN) and the same services to the outside world, so that the client 16a can access DC11 or DC12 through the LUN to handle the user's business. At this time, DC11 is responsible for generating, storing and managing the backup data 111 in DC11, and DC12 is responsible for generating, storing and managing the backup data 121 in DC12. DC13, as the disaster recovery center for storing backup data, is responsible for storing and managing the backup data 131 in DC13. DC14, as the disaster recovery center for storing backup data, is responsible for storing and managing the backup data 141 in DC14. In the event of a failure in DC11 or DC12, the access of the client 16a is switched to the surviving data center through the LUN. If both DC11 and DC12 fail, DC13 and DC14 form an active-active data center, jointly carrying services in first area 151. Specifically, DC13 and DC14 provide the same LUN and services, allowing client 16a to access DC13 or DC14 through the LUN to handle user services. In this case, DC13 is responsible for generating, storing, and managing backup data 131, while DC14 is responsible for generating, storing, and managing backup data 141.

[0066] In the disaster recovery system 10, a synchronous replication link is established between two data centers in the same region so that the two data centers in the same region synchronously replicate backup data. Establishing a synchronous replication link between two data centers in the same region includes:

[0067] (1) A first synchronous replication link 171 is established between DC11 and DC12. In a specific implementation, when the first synchronous replication link 171 is in a normal state, it is connected to DC11 and DC12 for communication, respectively, and is used to send the backup data 112 generated by DC11 to DC12, or to send the backup data 122 generated by DC12 to DC11, so that the backup data 111 in DC11 and the backup data 121 in DC12 are synchronized in real time to maintain consistency. In another specific implementation, when the first synchronous replication link 171 is in a normal state, it is also used to send the data 113 generated by the first change operation performed by DC11 according to the first business request 161 sent by the client 16a to DC12, or to send the data 123 generated by the second change operation performed by DC12 according to the second business request 162 sent by the client 16b to DC11. The first change operation or the second change operation includes an add operation, a write operation, a modify operation, a delete operation, and the like.

[0068] (2) A second synchronous replication link 172 is established between DC13 and DC14. In a specific implementation, when the second synchronous replication link 172 is in a normal state, it is connected to DC13 and DC14 for communication, and is used to send the backup data 132 in DC13 to DC14, or to send the backup data 142 in DC14 to DC13, so that the backup data 131 in DC13 and the backup data 141 in DC14 are synchronized in real time to maintain consistency. When both DC11 and DC12 fail and the second synchronous replication link 172 is in a normal state, the second synchronous replication link 172 is also used to send the data 133 generated by the third change operation performed by DC13 according to the business request sent by client 16a or client 16b to DC14, or to send the data 143 generated by the fourth change operation performed by DC14 according to the business request sent by client 16a or client 16b to DC14. The third change operation or the fourth change operation includes an add operation, a write operation, a modify operation, a delete operation, and the like.

[0069] In the disaster recovery system 10, an asynchronous replication link is established between two data centers in different regions, so that the two data centers in different regions asynchronously replicate backup data. Establishing an asynchronous replication link between two data centers in different regions includes:

[0070] (1) A first asynchronous replication link 173 is established between DC11 and DC13, with DC11 serving as the primary data center and DC13 serving as the secondary data center. When the first asynchronous replication link 173 is in normal state, it is connected to DC11 and DC13 for communication, and is used to send the backup data 112 generated by DC11 to DC13, so that DC13 stores the backup data 112, thereby ensuring that the backup data 131 in DC13 and the backup data 111 in DC11 are consistent. Typically, after DC11 generates the backup data 112, it sends it to DC12 in real time, and to DC13 in non-real time. For example, DC11 sends the backup data 112 to DC13 only during the asynchronous replication cycle.

[0071] (2) A second asynchronous replication link 174 is established between DC11 and DC14, with DC11 serving as the primary data center and DC14 serving as the secondary data center. When the second asynchronous replication link 174 is in a normal state, it is connected to DC11 and DC14 for communication, and is used to send the backup data 112 generated by DC11 to DC14, so that DC14 stores the backup data 112, thereby ensuring that the backup data 141 in DC14 and the backup data 111 in DC11 are consistent. Typically, after DC11 generates the backup data 112, it sends it to DC12 in real time, and to DC14 in non-real time. For example, DC11 sends the backup data 112 to DC14 only during the asynchronous replication cycle.

[0072] (3) A third asynchronous replication link 175 is established between DC12 and DC13, with DC12 serving as the primary data center and DC13 serving as the secondary data center. When the third asynchronous replication link 175 is in a normal state, it is connected to DC12 and DC13 for communication, and is used to send the backup data 122 generated by DC12 to DC13, so that DC13 stores the backup data 122, thereby ensuring that the backup data 131 in DC13 is consistent with the backup data 121 in DC12. Typically, after DC12 generates the backup data 122, it sends it to DC11 in real time, and to DC13 in non-real time. For example, DC12 sends the backup data 122 to DC13 only during the asynchronous replication cycle.

[0073] (4) A fourth asynchronous replication link 176 is established between DC12 and DC14, with DC12 serving as the primary data center and DC14 serving as the secondary data center. When the fourth asynchronous replication link 176 is in a normal state, it is connected to DC12 and DC14 for communication, and is used to send the backup data 122 generated by DC12 to DC14, so that DC14 stores the backup data 122, thereby ensuring that the backup data 141 in DC14 and the backup data 121 in DC12 are consistent. Typically, after DC12 generates the backup data 122, it sends it to DC11 in real time, and to DC14 in non-real time. For example, DC12 sends the backup data 122 to DC14 only during the asynchronous replication cycle.

[0074] In summary, a synchronous replication link is established between two data centers in the same region, and an asynchronous replication link is established between two data centers in different regions, thereby enabling full interconnection of all data centers in the disaster recovery system.

[0075] In some possible implementations, the backup data may be snapshots, logs, data files, etc. The following uses snapshots as an example of backup data to illustrate the operation mechanism of the disaster recovery system in conjunction with the structure of the disaster recovery system.

[0076] The disaster recovery system includes four data centers: Data Center A, Data Center B, Data Center C, and Data Center D. Data Center A and Data Center B are located in the first area 151, while Data Center C and Data Center D are located in the second area 152. The normal operation mechanism of the disaster recovery system requires that Data Centers A, B, C, and D all operate normally. In this case, the first synchronous replication link between Data Center A and Data Center B, the asynchronous replication link between Data Center A and Data Center C, and the second synchronous replication link between Data Center C and Data Center D can all operate normally, thereby achieving snapshot consistency across the four data centers.

[0077] 2A-2D, FIG2A is a schematic structural diagram of a disaster recovery system under a normal operating mechanism provided by the present application, and FIG2B, FIG2C, and FIG2D are schematic structural diagrams of a disaster recovery system under another normal operating mechanism provided by the present application.

[0078] In the disaster recovery system 10 shown in Figure 2A , data center A is DC11, data center B is DC12, data center C is DC13, and data center D is DC14. Therefore, the first synchronous replication link 171, the second synchronous replication link 172, and the first asynchronous replication link 173 can all be set to a normal state, and the second asynchronous replication link 174, the third asynchronous replication link 175, and the fourth asynchronous replication link 176 can all be set to a ready state, either manually or through software. The normal state indicates normal operation, while the ready state indicates inoperative operation. Based on this, the normal operation mechanism of the disaster recovery system 10 is as follows:

[0079] First, DC 11 takes a snapshot according to a first preset period, generating first snapshot 114. It then sends first snapshot 114 to DC 12 via first synchronous replication link 171, thereby synchronizing snapshot 125 stored in DC 12 with snapshot 115 stored in DC 11 in real time to maintain consistency. The first preset period is user-defined and can be one week, one day, one hour, or so on.

[0080] Next, during the asynchronous replication cycle, DC11 sends first snapshot 114 to DC13 via first asynchronous replication link 173, thereby synchronizing snapshot 135 stored in DC13 with snapshot 115 stored in DC11. The asynchronous replication cycle is user-defined and can be 3 weeks, 3 days, 3 hours, or the like.

[0081] Finally, after receiving first snapshot 114 from DC11 via first asynchronous replication link 173, DC13 performs a snapshot operation to generate third snapshot 134. It then sends third snapshot 134 to DC14 via second synchronous replication link 172, thereby synchronizing snapshot 145 stored in DC14 with snapshot 135 stored in DC13 in real time to maintain consistency. Alternatively, DC13 performs a snapshot operation according to a second preset period to generate third snapshot 134. The second preset period is determined by the user and can be one week, one day, one hour, or the like.

[0082] In some possible implementations, there may be one or more first snapshots 114. For example, when the first preset period is from 0:00 AM to 12:00 PM on the current day and the asynchronous replication period is from 12:00 PM to 10:00 PM on the current day, DC11 performs a snapshot operation at 0:00 AM every day, generates one first snapshot 114, and sends the first snapshot 114 to DC13 at 12:00 PM via the first asynchronous replication link 173. When the first preset period is from 0:00 AM to 12:00 PM on the current day and the asynchronous replication period is from 12:00 PM to 10:00 PM on the third day, DC11 performs a snapshot operation at 0:00 AM every day, generates a first snapshot 114, and thus, within the asynchronous replication period, DC11 needs to transmit a total of three first snapshots 114. DC11 can send the first snapshot 114 to DC13 through the first asynchronous replication link 173 every time it generates a first snapshot 114; it can also send the three first snapshots 114 together to DC13 through the first asynchronous replication link 173 after generating three first snapshots 114; it can also perform a snapshot operation on the three first snapshots 114 again after generating three first snapshots 114 to generate a new snapshot, and send the new snapshot to DC13 through the first asynchronous replication link 173. For DC13, it can perform a snapshot operation after receiving each first snapshot 114 to generate a third snapshot 134, and send the third snapshot 134 to DC14 through the second synchronous replication link 172; it can also perform a snapshot operation after receiving three first snapshots 114 to generate a third snapshot 134, and send the third snapshot 134 to DC14 through the second synchronous replication link 172; it can also perform a snapshot operation after receiving a new snapshot including three first snapshots 114 to generate a third snapshot 134, and send the third snapshot 134 to DC14 through the second synchronous replication link 172.

[0083] In summary, in the disaster recovery system 10 shown in FIG2A , the snapshots of the four data centers can be synchronized.

[0084] It should be understood that the transmission of first snapshot 114 between DC 11 and DC 12 is merely an example and is not intended to be a specific limitation. In the disaster recovery system 10 shown in FIG2A , DC 12 may also perform a snapshot operation according to a first preset period to generate a second snapshot 124, and then send the second snapshot 124 to DC 11 via the first synchronous replication link 171.

[0085] In the disaster recovery system 10 shown in Figure 2B , data center A is DC11, data center B is DC12, data center C is DC14, and data center D is DC13. Therefore, the first synchronous replication link 171, the second synchronous replication link 172, and the second asynchronous replication link 174 can all be set to a normal state, and the first asynchronous replication link 173, the third asynchronous replication link 175, and the fourth asynchronous replication link 176 can all be set to a ready state, either manually or through software. Based on this, the normal operating mechanism of the disaster recovery system 10 is as follows:

[0086] First, DC11 performs a snapshot operation according to a first preset period, generates a first snapshot 114, and sends first snapshot 114 to DC12 via first synchronous replication link 171, thereby synchronizing snapshot 125 stored in DC12 with snapshot 115 stored in DC11 in real time to maintain consistency. In a specific implementation, the first time DC11 performs a snapshot operation, it generates a full snapshot and uses the full snapshot as first snapshot 114. In subsequent snapshot operations, it generates incremental snapshots and uses the incremental snapshots as first snapshot 114.

[0087] Next, during the asynchronous replication cycle, DC11 sends the first snapshot 114 to DC14 via the second asynchronous replication link 174 , so that the snapshot 145 stored in DC14 and the snapshot 115 stored in DC11 are periodically synchronized to maintain consistency.

[0088] Finally, after receiving first snapshot 114 from DC11 via second asynchronous replication link 174, DC14 performs a snapshot operation to generate fourth snapshot 144. It then sends fourth snapshot 144 to DC13 via second synchronous replication link 172, thereby synchronizing snapshot 135 stored in DC13 with snapshot 145 stored in DC14 in real time to maintain consistency. Alternatively, DC14 performs a snapshot operation according to a second preset period to generate fourth snapshot 144.

[0089] In summary, in the disaster recovery system 10 shown in FIG2B , the snapshots of the four data centers can be synchronized.

[0090] In the disaster recovery system 10 shown in Figure 2C , data center A is DC12, data center B is DC11, data center C is DC13, and data center D is DC14. Therefore, the first synchronous replication link 171, the second synchronous replication link 172, and the third asynchronous replication link 175 can all be set to a normal state, and the first asynchronous replication link 173, the second asynchronous replication link 174, and the fourth asynchronous replication link 176 can all be set to a ready state, either manually or through software. Based on this, the normal operating mechanism of the disaster recovery system 10 is similar to that of the disaster recovery system 10 shown in Figure 2A above. For the sake of brevity, this description will not be repeated here.

[0091] In the disaster recovery system 10 shown in Figure 2D , data center A is DC12, data center B is DC11, data center C is DC14, and data center D is DC13. Therefore, the first synchronous replication link 171, the second synchronous replication link 172, and the fourth asynchronous replication link 176 can all be set to a normal state, and the first asynchronous replication link 173, the second asynchronous replication link 174, and the third asynchronous replication link 175 can all be set to a ready state, either manually or through software. Based on this, the normal operating mechanism of the disaster recovery system 10 is similar to that of the disaster recovery system 10 shown in Figure 2B above. For the sake of brevity, this description will not be repeated here.

[0092] In summary, when all four DCs are operating normally, the disaster recovery system can select the working asynchronous replication link, so the disaster recovery system has high flexibility.

[0093] Based on the structure and normal operation mechanism of the aforementioned disaster recovery system, a data synchronization method provided by the present application is specifically described below. This data synchronization method can be applied to the entire process of asynchronous replication, including asynchronous replication in the first cycle, asynchronous replication in the second cycle, ..., asynchronous replication in the kth cycle, where k is a positive integer, so that the backup data of two data centers from different regions remains consistent, and further the backup data of multiple data centers in the disaster recovery system remains consistent. The following uses the asynchronous replication in the kth cycle as an example to specifically describe a data synchronization method provided by the present application.

[0094] See Figure 3, which is a flow chart of a data synchronization method provided by the present application. As shown in Figure 3, the data synchronization method provided by the present application is applied to a disaster recovery system, wherein the disaster recovery system includes data center A, data center B, data center C, and data center D. The data synchronization method includes:

[0095] S301: Synchronize the snapshot A(t) of data center A and the snapshot B(t) of data center B in real time through the first synchronous replication link.

[0096] The first synchronous replication link may be the first synchronous replication link 171 in the disaster recovery system 10 in Figure 1 . Data center A and data center B are in the first region. Data center A may be DC11 or DC12 in the disaster recovery system 10 in Figure 1 . When data center A is DC11 in the disaster recovery system 10 in Figure 1 , data center B is DC12 in the disaster recovery system 10 in Figure 1 . When data center A is DC12 in the disaster recovery system 10 in Figure 1 , data center B is DC11 in the disaster recovery system 10 in Figure 1 . The first region may be the first region 151 in the disaster recovery system 10 in Figure 1 .

[0097] In some possible implementations, a snapshot includes metadata and data, where the metadata represents the attributes of the snapshot, including the name of the snapshot, the time the snapshot was generated, the name of the storage server, the file name, the file modification time, and so on. The data is the data in the storage server when the snapshot operation is performed. Taking snapshot A(t) as an example, snapshot A(t) includes metadata A(t) and data A(t). Metadata A(t) represents the attributes of snapshot A(t), including the name of snapshot A(t), the time t when snapshot A(t) was generated, the name of storage server A, the file name, the file modification time, and so on. Data A(t) is the data A(t) in storage server A when the snapshot operation is performed.

[0098] In one specific implementation, the snapshot also includes a global identifier, which is used to identify the data center that generated the snapshot. Taking snapshot A(t) as an example, the specific process for setting the global identifier t in snapshot A(t) is as follows: First, data center A can obtain the identifier of snapshot A(t). In one specific implementation, data center A sorts all snapshots A by their generation time, thereby obtaining a sequence number for each snapshot A(t), which serves as the identifier for snapshot A(t). It should be understood that the identifier for snapshot A(t) can also be the name of snapshot A(t), the generation time, etc. Next, since data center A is deployed on one or more storage servers A, data center A can obtain the identifier of storage server A. The identifier of storage server A can be a world wide name (WWN), a universally unique identifier (UUID), a device unique identifier (DUID), etc. In particular, when there are multiple storage servers A, data center A obtains the identifier of the storage server A that generated snapshot A(t). Subsequently, data center A combines the identifier of snapshot A(t) and the identifier of storage server A into a global identifier t, and adds the global identifier t to the metadata A(t) of snapshot A(t), thereby obtaining snapshot A(t) containing the global identifier t. In this scheme, multiple snapshots generated by the same storage server can be identified by the identifier of the snapshot; multiple snapshots generated by different storage servers can be identified by the identifier of the storage server. Therefore, in the case where the global identifier includes the identifier of the snapshot and the identifier of the storage server, all snapshots generated by all data centers can be uniquely identified by the global identifier, and all data centers can also store snapshots containing the same global identifier to ensure the consistency of snapshots in all data centers.

[0099] In some possible implementations, real-time synchronization of the snapshot A(t) of data center A and the snapshot B(t) of data center B via the first synchronous replication link includes at least the following two methods: (1) Data center B receives the snapshot A(t) generated by data center A via the first synchronous replication link and uses the snapshot A(t) as snapshot B(t). Specifically, after data center A generates the snapshot A(t) containing the global identifier t, it sends the snapshot A(t) to data center B via the first synchronous replication link. After data center B receives the snapshot A(t) sent by data center A via the first synchronous replication link, storage server B performs a write operation on the metadata A(t) and data A(t) in the snapshot A(t), and writes the metadata A(t) and data A(t) to storage server B. After the write operation is completed, data center B obtains snapshot B(t). (2) Data center A receives the snapshot B(t) generated by data center B via the first synchronous replication link and uses the snapshot B(t) as snapshot A(t). The specific process can refer to the above method (1) in which data center B receives the snapshot A(t) generated by data center A through the first synchronous replication link and uses the snapshot A(t) as the full snapshot B(t). For the sake of brevity, it will not be elaborated here.

[0100] S302: Periodically synchronize the snapshot A(t) of data center A and the snapshot C(t) of data center C through an asynchronous replication link.

[0101] In some possible implementations, when data center A is DC11 and data center C is DC13, the asynchronous replication link may be the first asynchronous replication link 173 in the disaster recovery system 10 in Figure 1 . When data center A is DC11 and data center C is DC14, the asynchronous replication link may be the second asynchronous replication link 174 in the disaster recovery system 10 in Figure 1 . When data center A is DC12 and data center C is DC13, the asynchronous replication link may be the third asynchronous replication link 175 in the disaster recovery system 10 in Figure 1 . When data center A is DC12 and data center C is DC14, the asynchronous replication link may be the fourth asynchronous replication link 176 in the disaster recovery system 10 in Figure 1 .

[0102] In some possible implementations, during an asynchronous replication cycle, data center A sends snapshot A(t) to data center C via an asynchronous replication link. After data center C receives snapshot A(t) from data center A via the asynchronous replication link, storage server C writes the metadata A(t) and data A(t) in snapshot A(t). After the write operation is complete, storage server C executes a snapshot operation to generate snapshot C(t).

[0103] S303: Synchronize the snapshot C(t) of data center C and the snapshot D(t) of data center D in real time through the second synchronous replication link.

[0104] The second synchronous replication link may be the second synchronous replication link 172 in the disaster recovery system 10 in FIG1 . Data center C and data center D are in a second region different from the first region. Data center C may be DC13 or DC14 in the disaster recovery system 10 in FIG1 . When data center C is DC13 in the disaster recovery system 10 in FIG1 , data center D is DC14 in the disaster recovery system 10 in FIG1 . When data center C is DC14 in the disaster recovery system 10 in FIG1 , data center D is DC13 in the disaster recovery system 10 in FIG1 . The second region may be the second region 152 in the disaster recovery system 10 in FIG1 .

[0105] In some possible implementations, after data center D receives snapshot C(t) from data center C via the second synchronous replication link, storage server D performs a write operation on the metadata C(t) and data C(t) in snapshot C(t). After the write operation is completed, data center D obtains snapshot D(t).

[0106] In summary, the data synchronization method proposed in this application is based on the realization of a fully interconnected network of four data centers in the disaster recovery system, synchronous replication of snapshots between two data centers in the same region, and asynchronous replication of snapshots between two data centers in different regions. With two data centers in different regions as the driving centers, the two data centers are caused to generate snapshots containing the same data during the asynchronous replication cycle, ensuring the consistency of the snapshots of the two data centers. At the same time, combined with the synchronous replication between the two data centers in the same region, the snapshots of the other two data centers are also consistent. Therefore, any two data centers have consistent snapshots.

[0107] However, when a failure occurs in the disaster recovery system 10, the disaster recovery system 10 can adjust the operating mechanism of the disaster recovery system 10 based on the type and number of failed data centers, the structure of the disaster recovery system 10 and the data synchronization method, to achieve a step-by-step decline in the disaster recovery performance of the disaster recovery system 10.

[0108] Below, this application will explain the operating mechanism of the disaster recovery system 10 under eleven different failure situations.

[0109] (1) Data Center A fails

[0110] Suppose Data Center A experiences a catastrophic failure, becoming completely unavailable, while Data Centers B, C, and D are all operating normally. In this case, because Data Centers A and B in the first region are active-active, client 16a currently processing services in Data Center A can seamlessly switch to Data Center B via the LUN, while client 16b currently processing services in Data Center B remains unaffected.

[0111] After a failure occurs in data center A, the disaster recovery system 10 includes at least the following two operating mechanisms:

[0112] a) Implement asynchronous replication of snapshots through the asynchronous replication link between data center B and data center C;

[0113] b) Asynchronous replication of snapshots is achieved through the asynchronous replication link between data center B and data center D.

[0114] It can be seen from this that the asynchronous replication link between data center B and data center C, and the asynchronous replication link between data center B and data center D are both backup asynchronous replication links.

[0115] Refer to Figure 4A, which is a schematic diagram of the operating mechanism of a disaster recovery system provided by the present application under the failure of data center A. As shown in Figure 4A, for the above situation a), the asynchronous replication link between data center B and data center C is set to a normal state manually or by software, so that the asynchronous replication link can work normally. After the asynchronous replication link can work normally, within the asynchronous replication cycle, data center B sends the snapshot B(n) to data center C through the asynchronous replication link. After data center C receives the snapshot B(n) sent by data center B through the asynchronous replication link, the storage server C performs a write operation on the metadata B(n) and data B(n) in the snapshot B(n). After completing the write operation, the storage server C performs a snapshot operation to generate a snapshot C(n), so that the snapshot C(n) of data center C and the snapshot B(n) of data center B are synchronized to maintain consistency. Subsequently, data center C sends the snapshot C(n) to data center D through a second synchronous replication link. After data center D receives snapshot C(n) from data center C via the second synchronous replication link, storage server D writes the metadata C(n) and data C(n) in snapshot C(n). After the write operation is complete, data center D obtains snapshot D(n), allowing snapshot D(n) in data center D to be synchronized with snapshot C(n) in data center C in real time to maintain consistency.

[0116] Refer to Figure 4B, which is a schematic diagram of the operating mechanism of another disaster recovery system provided by the present application under the failure of data center A. As shown in Figure 4B, for the above situation b), the asynchronous replication link between data center B and data center D is set to a normal state manually or by software, so that the asynchronous replication link can work normally. After the asynchronous replication link can work normally, within the asynchronous replication cycle, data center B sends the snapshot B(n) to data center D through the asynchronous replication link. After data center D receives the snapshot B(n) sent by data center B through the asynchronous replication link, the storage server D performs a write operation on the metadata B(n) and data B(n) in the snapshot B(n). After completing the write operation, the storage server D performs a snapshot operation to generate a snapshot D(n), so that the snapshot D(n) of data center D and the snapshot B(n) of data center B are synchronized to maintain consistency. Subsequently, data center D sends the snapshot D(n) to data center C through a second synchronous replication link. After data center C receives snapshot D(n) from data center D via the second synchronous replication link, storage server C writes the metadata D(n) and data D(n) in snapshot D(n). After the write operation is complete, data center C obtains snapshot C(n), thus synchronizing snapshot C(n) and snapshot D(n) in data center C in real time to maintain consistency.

[0117] (2) Data Center B fails

[0118] Assume that Data Center B experiences a catastrophic failure, while Data Centers A, C, and D are all operating normally. In this case, because Data Centers A and B in the first region are active-active, client 16b processing services in Data Center B can seamlessly switch to Data Center A through the LUN, while client 16a originally processing services in Data Center A remains unaffected.

[0119] See Figure 4C, which is a schematic diagram of the operating mechanism of a disaster recovery system provided by this application in the event of a failure in Data Center B. As shown in Figure 4C, after Data Center B fails, because the asynchronous replication link between Data Centers A and C continues to operate normally, Data Center A's snapshot A(n) and Data Center C's snapshot C(n) can be periodically synchronized to maintain consistency. Furthermore, in conjunction with synchronous replication between Data Centers C and D, Data Center C's snapshot C(n) and Data Center D's snapshot D(n) can be synchronized in real time to maintain consistency.

[0120] (3) Data Center C fails

[0121] Assume that Data Center C experiences a catastrophic failure, while Data Centers A, B, and D are all operating normally. In this case, client 16a processing services in Data Center A and client 16b processing services in Data Center B are not affected. Furthermore, because the first synchronous replication link between Data Centers A and B is still functioning normally, snapshots A(n) in Data Center A and B(n) in Data Center B can be synchronized in real time to maintain consistency.

[0122] After a failure occurs in data center C, the disaster recovery system 10 includes at least the following two operating mechanisms:

[0123] a) Asynchronous replication of snapshots is achieved through the asynchronous replication link between data center A and data center D;

[0124] b) Asynchronous replication of snapshots is achieved through the asynchronous replication link between data center B and data center D.

[0125] It can be seen from this that the asynchronous replication link between data center A and data center D and the asynchronous replication link between data center B and data center D are backup asynchronous replication links.

[0126] See Figure 4D, which is a schematic diagram of the operating mechanism of a disaster recovery system provided by the present application under the failure of data center C. As shown in Figure 4D, for the above situation a), the asynchronous replication link between data center A and data center D is set to a normal state manually or by software, so that the asynchronous replication link can work normally. After the asynchronous replication link can work normally, within the asynchronous replication cycle, data center A sends the snapshot A(n) to data center D through the asynchronous replication link. After data center D receives the snapshot A(n) sent by data center A through the asynchronous replication link, the storage server D performs a write operation on the metadata A(n) and data A(n) in the snapshot A(n). After completing the write operation, the storage server D performs a snapshot operation to generate a snapshot D(n), so that the snapshot D(n) of data center D and the snapshot A(n) of data center A are synchronized to maintain consistency.

[0127] See Figure 4E, which is a schematic diagram of the operating mechanism of another disaster recovery system provided by the present application under the failure of data center C. As shown in Figure 4E, for the above situation b), the asynchronous replication link between data center B and data center D is set to a normal state manually or by software, so that the asynchronous replication link can work normally. After the asynchronous replication link can work normally, within the asynchronous replication cycle, data center B sends the snapshot B(n) to data center D through the asynchronous replication link. After data center D receives the snapshot B(n) sent by data center B through the asynchronous replication link, the storage server D performs a write operation on the metadata B(n) and data B(n) in the snapshot B(n). After completing the write operation, the storage server D performs a snapshot operation to generate a snapshot D(n), so that the snapshot D(n) of data center D and the snapshot B(n) of data center B are synchronized to maintain consistency.

[0128] (4) Data Center D fails

[0129] Assume that Data Center D experiences a catastrophic failure, while Data Centers A, B, and C are all operating normally. In this case, client 16a processing services in Data Center A and client 16b processing services in Data Center B are not affected. Furthermore, because the first synchronous replication link between Data Centers A and B is still operating normally, snapshots A(n) in Data Center A and B(n) in Data Center B can be synchronized in real time to maintain consistency.

[0130] See Figure 4F, which is a schematic diagram of the operation mechanism of a disaster recovery system provided by this application under the failure of data center D. As shown in Figure 4F, after the failure of data center D, because the asynchronous replication link between data centers A and C is still functioning normally, snapshots A(n) of data center A and snapshots C(n) of data center C can be periodically synchronized to maintain consistency.

[0131] To sum up, after a sudden failure in any data center, there is a disaster recovery protection relationship between any two of the remaining three data centers in the disaster recovery system 10, and snapshot synchronization of the three data centers can be achieved. Therefore, the disaster recovery scale of the disaster recovery system 10 is reduced from four to three, and the disaster recovery performance decreases step by step, which can meet user demands to the greatest extent.

[0132] (5) Data Centers A and B experience a failure

[0133] Assume that data centers A and B experience a catastrophic failure while data centers C and D are operating normally. At this time, client 16a processing services on data center A is forced to be disconnected, and client 16b processing services on data center B is also forced to be disconnected.

[0134] See FIG4G , which is a schematic diagram of the operating mechanism of a disaster recovery system provided by this application in the event of a failure in data centers A and B. As shown in FIG4G , after a failure in data centers A and B occurs, the services of data centers A and B are manually switched to data centers C and D. Data centers C and D form an active-active data center, providing the same LUN and the same services to the outside world. This allows clients 16a and 16b to access data center C or data center D through the LUN and re-process their services in data center C or data center D. This also allows snapshots C(n) of data center C and snapshots D(n) of data center D to be synchronized in real time to maintain consistency.

[0135] (6) Data Centers A and C fail

[0136] Assume that data centers A and C experience a catastrophic failure, while data centers B and D remain operational. Since data centers A and B in the first region are active-active, client 16a currently processing services in data center A can seamlessly switch to data center B via the LUN, while client 16b currently processing services in data center B remains unaffected.

[0137] See Figure 4H, which is a schematic diagram of the operating mechanism of a disaster recovery system provided by the present application under failure of data centers A and C. As shown in Figure 4H, after a failure occurs in data centers A and C, the asynchronous replication link between data center B and data center D is set to a normal state manually or by software, so that the asynchronous replication link can operate normally. After the asynchronous replication link can operate normally, within the asynchronous replication cycle, data center B sends the snapshot B(n) to data center D through the asynchronous replication link. After data center D receives the snapshot B(n) sent by data center B through the asynchronous replication link, the storage server D performs a write operation on the metadata B(n) and data B(n) in the snapshot B(n). After completing the write operation, the storage server D performs a snapshot operation to generate a snapshot D(n), so that the snapshot D(n) of data center D and the snapshot B(n) of data center B are synchronized to maintain consistency.

[0138] This shows that the asynchronous replication link between data center B and data center D is a backup asynchronous replication link.

[0139] (7) Data Centers A and D fail

[0140] Assume that data centers A and D experience a catastrophic failure, while data centers B and D remain operational. Since data centers A and B in the first region are active-active, client 16a currently processing services in data center A can seamlessly switch to data center B via the LUN, while client 16b currently processing services in data center B remains unaffected.

[0141] See Figure 4I, which is a schematic diagram of the operating mechanism of a disaster recovery system provided by the present application under the failure of data centers A and D. As shown in Figure 4I, after a failure occurs in data centers A and D, the asynchronous replication link between data center B and data center C is set to a normal state manually or by software, so that the asynchronous replication link can work normally. After the asynchronous replication link can work normally, within the asynchronous replication cycle, data center B sends the snapshot B(n) to data center C through the asynchronous replication link. After data center C receives the snapshot B(n) sent by data center B through the asynchronous replication link, the storage server C performs a write operation on the metadata B(n) and data B(n) in the snapshot B(n). After completing the write operation, the storage server C performs a snapshot operation to generate a snapshot C(n), so that the snapshot C(n) of data center C and the snapshot B(n) of data center B are synchronized to maintain consistency.

[0142] This shows that the asynchronous replication link between data center B and data center C is a backup asynchronous replication link.

[0143] (8) Data Centers B and C fail

[0144] Assume that data centers B and C experience a catastrophic failure, while data centers A and D remain operational. Since data centers A and B in the first region are active-active, client 16b processing services in data center B can seamlessly switch to data center A through the LUN, while client 16a processing services in data center A remains unaffected.

[0145] See Figure 4J, which is a schematic diagram of the operating mechanism of a disaster recovery system provided by the present application under failure of data centers B and C. As shown in Figure 4J, after a failure occurs in data centers B and C, the asynchronous replication link between data center A and data center D is set to a normal state manually or by software, so that the asynchronous replication link can work normally. After the asynchronous replication link can work normally, within the asynchronous replication cycle, data center A sends the snapshot A(n) to data center D through the asynchronous replication link. After data center D receives the snapshot A(n) sent by data center A through the asynchronous replication link, the storage server D performs a write operation on the metadata A(n) and data A(n) in the snapshot A(n). After completing the write operation, the storage server D performs a snapshot operation to generate a snapshot D(n), so that the snapshot D(n) of data center D and the snapshot A(n) of data center A are synchronized to maintain consistency.

[0146] This shows that the asynchronous replication link between data center A and data center D is a backup asynchronous replication link.

[0147] (9) Data Centers B and D fail

[0148] Assume that data centers B and D experience a catastrophic failure, while data centers A and C remain operational. Since data centers A and B in the first region are active-active, client 16b processing services in data center B can seamlessly switch to data center A through the LUN, while client 16a processing services in data center A remains unaffected.

[0149] See Figure 4K, which is a schematic diagram of the operation mechanism of a disaster recovery system provided by this application under the failure of data centers B and D. As shown in Figure 4K, after the failure of data centers B and D, because the asynchronous replication link between data centers A and C is still functioning normally, snapshots A(n) of data center A and snapshots C(n) of data center C can be periodically synchronized to maintain consistency.

[0150] (10) Data Centers C and D fail

[0151] Assume that data centers C and D experience a catastrophic failure while data centers A and B are operating normally. In this case, client 16a processing services in data center A and client 16b processing services in data center B are not affected.

[0152] See Figure 4L, which is a schematic diagram of the operating mechanism of a disaster recovery system provided by this application under the failure of data centers C and D. As shown in Figure 4L, after the failure of data centers C and D, because the first synchronous replication link between data centers A and B is still functioning normally, snapshot A(n) of data center A and snapshot B(n) of data center B can be synchronized in real time to maintain consistency.

[0153] To sum up, after any two data centers suddenly fail, the remaining two data centers in the disaster recovery system 10 still have a disaster recovery protection relationship, and snapshot synchronization of the two data centers can be achieved. Therefore, the disaster recovery scale of the disaster recovery system 10 is reduced from four to two, and the disaster recovery performance decreases step by step, which can meet user demands to the greatest extent.

[0154] (11) The asynchronous replication link between data center A and data center C fails

[0155] Assume that the asynchronous replication link between data centers A and C fails, while data centers A, B, C, and D are all operating normally. In this case, client 16a processing services in data center A and client 16b processing services in data center B are not affected. Furthermore, because the first synchronous replication link between data centers A and B is still operating normally, snapshots A(n) in data center A and B(n) in data center B can be synchronized in real time to maintain consistency.

[0156] After the asynchronous replication link between data center A and data center C fails, the disaster recovery system 10 includes at least the following three operating mechanisms:

[0157] a) Asynchronous replication of snapshots is achieved through the asynchronous replication link between data center A and data center D;

[0158] b) Asynchronous replication of snapshots is achieved through the asynchronous replication link between data center B and data center C;

[0159] c) Asynchronous replication of snapshots is achieved through the asynchronous replication link between data center B and data center D.

[0160] It can be seen that the asynchronous replication link between data center A and data center D, the asynchronous replication link between data center B and data center C, and the asynchronous replication link between data center B and data center D are all backup asynchronous replication links.

[0161] Refer to Figure 4M, which is a schematic diagram of the operating mechanism of a disaster recovery system provided by the present application under the failure of the asynchronous replication link between data centers A and C. As shown in Figure 4M, for the above situation a), the asynchronous replication link between data center A and data center D is set to a normal state manually or by software, so that the asynchronous replication link can work normally. After the asynchronous replication link can work normally, within the asynchronous replication cycle, data center A sends the snapshot A(n) to data center D through the asynchronous replication link. After data center D receives the snapshot A(n) sent by data center A through the asynchronous replication link, the storage server D performs a write operation on the metadata A(n) and data A(n) in the snapshot A(n). After completing the write operation, the storage server D performs a snapshot operation to generate a snapshot D(n), so that the snapshot D(n) of data center D and the snapshot A(n) of data center A are synchronized periodically to maintain consistency. Subsequently, data center D sends the snapshot D(n) to data center C through a second synchronous replication link. After data center C receives snapshot D(n) from data center D via the second synchronous replication link, storage server C writes the metadata D(n) and data D(n) in snapshot D(n). After the write operation is complete, data center C obtains snapshot C(n), thus synchronizing snapshot C(n) and snapshot D(n) in data center C in real time to maintain consistency.

[0162] Refer to Figure 4N, which is a schematic diagram of the operating mechanism of another disaster recovery system provided by the present application under the failure of the asynchronous replication link between data centers A and C. As shown in Figure 4N, for the above situation b), the asynchronous replication link between data center B and data center C is set to a normal state manually or by software, so that the asynchronous replication link can operate normally. After the asynchronous replication link can operate normally, within the asynchronous replication cycle, data center B sends the snapshot B(n) to data center C through the asynchronous replication link. After data center C receives the snapshot B(n) sent by data center B through the asynchronous replication link, the storage server C performs a write operation on the metadata B(n) and data B(n) in the snapshot B(n). After completing the write operation, the storage server C performs a snapshot operation to generate a snapshot C(n), so that the snapshot C(n) of data center C and the snapshot B(n) of data center B are synchronized to maintain consistency. Subsequently, data center C sends the snapshot C(n) to data center D through a second synchronous replication link. After data center D receives snapshot C(n) from data center C via the second synchronous replication link, storage server D writes the metadata C(n) and data C(n) in snapshot C(n). After the write operation is complete, data center D obtains snapshot D(n), allowing snapshot D(n) in data center D to be synchronized with snapshot C(n) in data center C in real time to maintain consistency.

[0163] Refer to Figure 4O, which is a schematic diagram of the operating mechanism of another disaster recovery system provided by the present application under the failure of the asynchronous replication link between data centers A and C. As shown in Figure 4O, for the above situation c), the asynchronous replication link between data center B and data center D is set to a normal state manually or by software, so that the asynchronous replication link can work normally. After the asynchronous replication link can work normally, within the asynchronous replication cycle, data center B sends the snapshot B(n) to data center D through the asynchronous replication link. After data center D receives the snapshot B(n) sent by data center B through the asynchronous replication link, the storage server D performs a write operation on the metadata B(n) and data B(n) in the snapshot B(n). After completing the write operation, the storage server D performs a snapshot operation to generate a snapshot D(n), so that the snapshot D(n) of data center D and the snapshot B(n) of data center B are synchronized to maintain consistency. Subsequently, data center D sends the snapshot D(n) to data center C through a second synchronous replication link. After data center C receives snapshot D(n) from data center D via the second synchronous replication link, storage server C writes the metadata D(n) and data D(n) in snapshot D(n). After the write operation is complete, data center C obtains snapshot C(n), thus synchronizing snapshot C(n) and snapshot D(n) in data center C in real time to maintain consistency.

[0164] It should be understood that the failure of the asynchronous replication link between data center A and data center C mentioned above is only an example of a link failure. It can also be the failure of the asynchronous replication link between data center A and data center D, the failure of the asynchronous replication link between data center B and data center C, the failure of the asynchronous replication link between data center B and data center D, etc., which is not specifically limited here.

[0165] To summarize, if any one of the asynchronous replication links suddenly fails, the remaining three asynchronous replication links in the disaster recovery system 10 can still implement asynchronous replication of snapshots, thereby achieving snapshot synchronization of four data centers, ensuring that the disaster recovery scale of the disaster recovery system 10 is still four. Furthermore, if any two of the asynchronous replication links suddenly fail, for example, two asynchronous replication links fail at the same time, or after one asynchronous replication link fails, the other asynchronous replication link also fails after working normally for a period of time, the remaining two asynchronous replication links in the disaster recovery system 10 can still implement asynchronous replication of snapshots, thereby achieving snapshot synchronization of four data centers, ensuring that the disaster recovery scale of the disaster recovery system 10 is still four. Furthermore, if any three of the asynchronous replication links suddenly fail, the remaining one asynchronous replication link in the disaster recovery system 10 can still implement asynchronous replication of snapshots, thereby achieving snapshot synchronization of four data centers, ensuring that the disaster recovery scale of the disaster recovery system 10 is still four. It can be seen from this that the four asynchronous replication links in the disaster recovery system 10 serve as backup links for each other.

[0166] Based on the operating mechanism of the above-mentioned disaster recovery system, the following describes a disaster recovery method provided by this application. This disaster recovery method can be applied to the disaster recovery system provided by this application, so that the disaster recovery performance of the disaster recovery system can be reduced in a step-by-step manner when a data center failure occurs, thereby maximally meeting user demands.

[0167] See Figure 5, which is a flow chart of a disaster recovery method provided by the present application. As shown in Figure 5, the disaster recovery method provided by the present application includes:

[0168] S501: Determine whether there is a fault in data center A, B, C, or D. If there is no fault, go to S502; if there is a fault, go to S505.

[0169] S502: Synchronize the snapshot A(n) of data center A and the snapshot B(n) of data center B in real time through the first synchronous replication link.

[0170] S503: Periodically synchronize the snapshot A(n) of data center A and the snapshot C(n) of data center C through an asynchronous replication link.

[0171] S504: Synchronize the snapshot C(n) of data center C and the snapshot D(n) of data center D in real time through the second synchronous replication link.

[0172] S505: Use a preset disaster recovery solution to keep the snapshot of the normally operating data center consistent.

[0173] The first synchronous replication link can be the first synchronous replication link 171 in the disaster recovery system 10 in Figure 1 , and the second synchronous replication link can be the second synchronous replication link 172 in the disaster recovery system 10 in Figure 1 . Data center A can be DC11 or DC12 in the disaster recovery system 10 in Figure 1 . When data center A is DC11, data center C is DC13, and data center B is DC12, the asynchronous replication link is the first asynchronous replication link 173. When data center A is DC11 and data center C is DC14, data center B is DC12, and the asynchronous replication link is the second asynchronous replication link 174. When data center A is DC12 and data center C is DC13, data center B is DC11, and the asynchronous replication link is the third asynchronous replication link 175. When data center A is DC12, data center C is DC14, and data center B is DC11, the asynchronous replication link is the fourth asynchronous replication link 176.

[0174] The execution process of the above steps S502 to S504 can refer to the execution process of steps S301 to S303 in Figure 3, and for the sake of brevity, they will not be elaborated here.

[0175] Referring to FIG. 5A , FIG. 5A is a flow chart illustrating a method of using a preset disaster recovery solution in the event of a failure in data center A. In the event of a failure in data center A, step S505 in FIG. 5 , which employs the preset disaster recovery solution to maintain consistency in snapshots of the normally operating data center, specifically includes:

[0176] S511: Set the asynchronous replication link between data center B and data center a to a normal state, where data center a is any one of data centers C and D.

[0177] S512: Periodically synchronize the snapshot B(n) of data center B with the snapshot a(n) of data center a through the asynchronous replication link.

[0178] S513: Synchronize the snapshot a(n) of data center a and the snapshot b(n) of data center b in real time through the second synchronous replication link, where data center b is the other data center among data centers C and D.

[0179] This embodiment corresponds to FIG. 4A , FIG. 4B and their related descriptions, and they can be implemented by reference to each other, and the repeated parts will not be repeated.

[0180] Referring to FIG. 5B , FIG. 5B is a flow chart illustrating a method of using a preset disaster recovery solution in the event of a failure in data center C. In the event of a failure in data center C, step S505 in FIG. 5 , which employs the preset disaster recovery solution to maintain consistency in snapshots of the normally operating data center, specifically includes:

[0181] S521: Set the asynchronous replication link between data center a and data center D to a normal state, where data center a is any one of data centers A and B.

[0182] S522: Periodically synchronize the snapshot a(n) of data center a with the snapshot D(n) of data center D through the asynchronous replication link.

[0183] This embodiment corresponds to FIG. 4D , FIG. 4E and their related descriptions, and they can be implemented by reference to each other, and the repeated parts will not be repeated.

[0184] Referring to FIG. 5C , FIG. 5C is a flow chart illustrating a method for implementing a preset disaster recovery solution in the event of a failure in two data centers, as provided herein. In the event that both data centers A and C fail, or both data centers A and D fail, or both data centers B and C fail, step S505 in FIG. 5 , which employs the preset disaster recovery solution to maintain consistency in snapshots of the normally operating data centers, specifically includes:

[0185] S531: Set the asynchronous replication link between data center a and data center b to a normal state, where data center a is the data center that has not failed among data centers A and B, and data center b is the data center that has not failed among data centers C and D.

[0186] S532: Periodically synchronize snapshot a(n) of data center a with snapshot b(n) of data center b through an asynchronous replication link.

[0187] This embodiment corresponds to FIG. 4H , FIG. 4I , FIG. 4J and their related descriptions, and they can be implemented by reference to each other, and the repeated parts will not be repeated.

[0188] Referring to FIG. 5D , FIG. 5D is a flow chart of a preset disaster recovery solution provided by the present application for the case of a failure of any asynchronous replication link. In the event of a failure of the asynchronous replication link between data center A and data center C, or a failure of the asynchronous replication link between data center A and data center D, or a failure of the asynchronous replication link between data center B and data center C, or a failure of the asynchronous replication link between data center B and data center D, step S505 in FIG. 5 above: adopting the preset disaster recovery solution to maintain the consistency of the snapshots of the normally operating data centers, specifically includes:

[0189] S541: Set the asynchronous replication link that has not failed to be in a normal state.

[0190] S542: Periodically synchronize snapshot a(n) of data center a and snapshot b(n) of data center b through an asynchronous replication link that has not failed, where data centers a and b are data centers at both ends of the asynchronous replication link that has not failed, and data center a is in the first region and data center b is in the second region.

[0191] This embodiment corresponds to Figure 4M, Figure 4N, Figure 4O and their related descriptions, and you can refer to each other for implementation. The repeated parts will not be repeated.

[0192] To sum up, the disaster recovery method proposed in this application, based on the full interconnection of four data centers in the disaster recovery system, can realize snapshot synchronization of the data centers at both ends through the normally operating asynchronous replication link as long as there is still an asynchronous replication link that can operate normally, so that the snapshots of the data centers that are still operating normally remain consistent, and a disaster recovery protection relationship is established between any two data centers that are still operating normally, thereby realizing a step-by-step decline in the disaster recovery performance of the disaster recovery system and maximizing the satisfaction of user demands.

[0193] 6 , which is a schematic diagram of the structure of a disaster recovery device provided by the present application. Disaster recovery device 600 is used as a first disaster recovery device and can implement the aforementioned disaster recovery method. As shown in FIG6 , disaster recovery device 600 includes: a synchronous replication module 601 and an asynchronous replication module 602 .

[0194] The synchronous replication module 601 is used to synchronously replicate the backup data to the second disaster recovery device through the first synchronous replication link;

[0195] The asynchronous replication module 602 is configured to asynchronously replicate the backup data to the third disaster recovery device through the first asynchronous replication link when the third disaster recovery device is normal;

[0196] The asynchronous replication module 602 is further configured to asynchronously replicate the backup data to the fourth disaster recovery device via the second asynchronous replication link when a failure occurs in the third disaster recovery device;

[0197] Among them, disaster recovery device 600 and the second disaster recovery device are both production centers, disaster recovery device 600 and the second disaster recovery device are located in the first area, the third disaster recovery device and the fourth disaster recovery device are both disaster recovery centers, and the third disaster recovery device and the fourth disaster recovery device are located in the second area different from the first area.

[0198] In some possible implementations, the backup data is a snapshot or a log.

[0199] In some possible implementations, the disaster recovery device 600 and the second disaster recovery device provide the same services and the same logical unit number LUN to the outside world, so that the client accesses the disaster recovery device 600 or the second disaster recovery device through the LUN, and in the event of a failure of the disaster recovery device 600 or the second disaster recovery device, the client's access is switched to the surviving disaster recovery device through the LUN.

[0200] In some possible implementations, the synchronous replication module 601 is specifically configured to synchronously replicate the backup data and the data generated by the client accessing the disaster recovery device 600 to the second disaster recovery device through the first synchronous replication link.

[0201] Both the synchronous replication module 601 and the asynchronous replication module 602 can be implemented in software or hardware. For example, the implementation of the synchronous replication module 601 will be described below using the synchronous replication module 601 as an example. Similarly, the implementation of the asynchronous replication module 602 can refer to the implementation of the synchronous replication module 601.

[0202] As an example of a software functional unit, the synchronous replication module 601 may include code running on a computing instance. The computing instance may include at least one of a physical host (computing device), a virtual machine, and a container. Furthermore, the computing instance may be one or more. For example, the synchronous replication module 601 may include code running on multiple hosts / virtual machines / containers. It should be noted that the multiple hosts / virtual machines / containers used to run the code may be distributed in the same region or in different regions. Furthermore, the multiple hosts / virtual machines / containers used to run the code may be distributed in the same availability zone (AZ) or in different AZs, each AZ including one data center or multiple geographically close data centers. Typically, a region may include multiple AZs.

[0203] Similarly, multiple hosts / virtual machines / containers running the code can be distributed within the same virtual private cloud (VPC) or across multiple VPCs. Typically, a VPC is set up within a region. Cross-region communication between two VPCs within the same region, or between VPCs in different regions, requires a communication gateway within each VPC to interconnect the VPCs.

[0204] As an example of a hardware functional unit, the synchronous replication module 601 may include at least one computing device, such as a server. Alternatively, the synchronous replication module 601 may be implemented using an application-specific integrated circuit (ASIC) or a programmable logic device (PLD). The PLD may be a complex programmable logical device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0205] The multiple computing devices included in the synchronous replication module 601 can be distributed in the same region or in different regions. The multiple computing devices included in the synchronous replication module 601 can be distributed in the same AZ or in different AZs. Similarly, the multiple computing devices included in the synchronous replication module 601 can be distributed in the same VPC or in multiple VPCs. The multiple computing devices can be any combination of servers, ASICs, PLDs, CPLDs, FPGAs, GALs, and other computing devices.

[0206] It should be noted that, in other embodiments, the synchronous replication module 601 can be used to execute any step in the disaster recovery method, and the asynchronous replication module 602 can be used to execute any step in the disaster recovery method. The steps that the synchronous replication module 601 and the asynchronous replication module 602 are responsible for implementing can be specified as needed. The full functions of the disaster recovery device 600 are realized by respectively implementing different steps in the disaster recovery method through the synchronous replication module 601 and the asynchronous replication module 602.

[0207] According to the disaster recovery method provided in the present application, the present application also provides a disaster recovery system, which includes the aforementioned disaster recovery device 600.

[0208] Referring to Figure 7 , which is a schematic diagram of the structure of a storage server provided by this application. As shown in Figure 7 , storage server 700 includes a bus 701, a processor 702, a memory 703, and a communication interface 704. Processor 702, memory 703, and communication interface 704 communicate with each other via bus 701. It should be understood that this application does not limit the number of processors and memories in storage server 700.

[0209] Bus 701 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, among others. Buses may be classified as address buses, data buses, control buses, and the like. For ease of illustration, FIG7 illustrates a single bus line, but this does not imply a single bus or type of bus. Bus 701 may include a path for transmitting information between various components of storage server 700 (e.g., memory 703, processor 702, and communication interface 704).

[0210] The processor 702 may include any one or more processors such as a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor (MP), or a digital signal processor (DSP).

[0211] The memory 703 may include a volatile memory, such as a random access memory (RAM). The memory 703 may also include a non-volatile memory, such as a read-only memory (ROM), a flash memory, a hard disk drive (HDD), or a solid state drive (SSD).

[0212] The memory 703 stores executable program codes, and the processor 702 executes the executable program codes to respectively implement the functions of the aforementioned synchronous replication module 601 and asynchronous replication module 602, thereby implementing the disaster recovery method. That is, the memory 703 stores instructions for executing the disaster recovery method.

[0213] The communication interface 704 uses a transceiver unit such as, but not limited to, a network interface card or a transceiver to implement communication between the storage server 700 and other devices or a communication network.

[0214] According to the disaster recovery method provided in this application, this application also provides a disaster recovery system, which includes the aforementioned storage server 700.

[0215] The present application also provides a computer program product comprising instructions. The computer program product may be software or a program product comprising instructions that can be executed on a computing device or stored in any usable medium. When the computer program product is executed on at least one computing device, the computer program product causes the at least one computing device to execute a disaster recovery method.

[0216] The present application also provides a computer-readable storage medium. The computer-readable storage medium can be any available medium capable of being stored by a computing device, or a data storage device such as a data center that contains one or more available media. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive). The computer-readable storage medium includes instructions that instruct the computing device to execute a disaster recovery method.

[0217] It should be understood that in the embodiments of the present invention, "when..." and "when..." both mean that the device will perform corresponding processing under certain objective circumstances, and do not limit the time. It does not require the device to perform a judgment action when it is implemented, nor does it mean that there are other limitations.

[0218] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the protection scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A disaster recovery system, characterized in that: include: a first data center, a second data center, a third data center, and a fourth data center, wherein the first data center and the second data center are both production centers, the third data center and the fourth data center are both disaster recovery centers, the first data center and the second data center are located in a first area, and the third data center and the fourth data center are located in a second area different from the first area, There is a first synchronous replication link between the first data center and the second data center; There is a second synchronous replication link between the third data center and the fourth data center; There is a first asynchronous replication link between the first data center and the third data center; Furthermore, the disaster recovery system further includes one, two or three of the following backup asynchronous replication links: A second asynchronous replication link is provided between the first data center and the fourth data center; A third asynchronous replication link is provided between the second data center and the third data center; A fourth asynchronous replication link is provided between the second data center and the fourth data center.

2. The disaster recovery system according to claim 1, characterized in that: The synchronous replication link is used to synchronously replicate the backup data of the data centers at both ends of the synchronous replication link; the asynchronous replication link is used to asynchronously replicate the backup data of the data centers at both ends of the asynchronous replication link.

3. The disaster recovery system according to claim 1 or 2, characterized in that: In the event that a failure occurs in the first data center or the third data center, the backup asynchronous replication link is used to asynchronously replicate the backup data between the first area and the second area.

4. The disaster recovery system according to any one of claims 1 to 3, characterized in that: The plurality of backup asynchronous replication links serve as backup links for each other.

5. The disaster recovery system according to any one of claims 2 to 4, characterized in that: The backup data is a snapshot or a log.

6. The disaster recovery system according to any one of claims 1 to 5, characterized in that: The first data center and the second data center are active-active data centers. The first data center and the second data center are used to provide the same services and the same logical unit number LUN to the outside world, so that the client can access the first data center or the second data center through the LUN, and in the event of a failure of the first data center or the second data center, the client's access is switched to the surviving data center through the LUN.

7. The disaster recovery system according to any one of claims 1 to 6, characterized in that: The third data center and the fourth data center are active-active data centers, and the third data center and the fourth data center are used to provide the same services and the same logical unit number LUN to the outside world, so that the client can access the third data center or the fourth data center through the LUN, and in the event of a failure of the third data center or the fourth data center, the client's access is switched to a surviving data center through the LUN.

8. A disaster recovery method, characterized in that: include: The first data center synchronously replicates backup data to the second data center through a first synchronous replication link, wherein the first data center and the second data center are both production centers, and the first data center and the second data center are located in a first region; When the third data center is normal, the first data center asynchronously replicates the backup data to the third data center through a first asynchronous replication link, wherein the third data center is a disaster recovery center and is located in a second area different from the first area; In the event of a failure of the third data center, the first data center asynchronously replicates the backup data to a fourth data center via a second asynchronous replication link, wherein the fourth data center is a disaster recovery center and is located in the second region.

9. The method according to claim 8, characterized in that The method further comprises: In the event of a failure in the first data center, the second data center asynchronously replicates to the third data center through a third asynchronous replication link. Alternatively, the second data center asynchronously replicates the backup data to the fourth data center through a fourth asynchronous replication link.

10. The method according to claim 8 or 9, characterized in that: The backup data is a snapshot or a log.

11. The method according to any one of claims 8 to 10, characterized in that: The first data center and the second data center are active-active data centers. The first data center and the second data center provide the same services and the same logical unit number LUN to the outside world, so that the client accesses the first data center or the second data center through the LUN, and in the event of a failure of the first data center or the second data center, the client's access is switched to the surviving data center through the LUN.

12. The method according to claim 11, characterized in that The first data center synchronously replicates the backup data to the second data center through the first synchronous replication link, including: The first data center synchronously replicates the backup data and data generated according to the client's access to the first data center to the second data center through the first synchronous replication link.

13. The method according to any one of claims 8 to 12, characterized in that: The third data center and the fourth data center are active-active data centers. The third data center and the fourth data center provide the same services and the same logical unit number LUN to the outside world, so that the client accesses the third data center or the fourth data center through the LUN, and in the event of a failure of the third data center or the fourth data center, the client's access is switched to a surviving data center through the LUN.

14. A disaster recovery device, characterized in that: Used as a first disaster recovery device, including: a synchronous replication module and an asynchronous replication module, The synchronous replication module is used to synchronously replicate the backup data to the second disaster recovery device through the first synchronous replication link, wherein the first disaster recovery device and the second disaster recovery device are both production centers, and the first disaster recovery device and the second disaster recovery device are located in the first area; The asynchronous replication module is used to asynchronously replicate the backup data to the third disaster recovery device through the first asynchronous replication link when the third disaster recovery device is normal, wherein the third disaster recovery device is a disaster recovery center and is located in a second area different from the first area; The asynchronous replication module is also used to asynchronously replicate the backup data to a fourth disaster recovery device through a second asynchronous replication link when the third disaster recovery device fails, wherein the fourth disaster recovery device is a disaster recovery center and is located in the second area.

15. A storage server, characterized in that: It includes a processor and a memory, the memory is used to store instructions, and the processor is used to execute the instructions. When the processor executes the instructions, the disaster recovery method according to any one of claims 8 to 13 is implemented.

16. A computer program product comprising instructions, characterized in that When the instructions are executed by a computing device, the computing device executes the disaster recovery method according to any one of claims 8 to 13.

17. A computer-readable storage medium, characterized in that: The method comprises computer program instructions. When the computer program instructions are executed by a computing device, the computing device executes the disaster recovery method according to any one of claims 8 to 13.

Images