Backup system and backup method

Abstract

To provide a backup system and a backup method capable of maintaining the robustness of backup operation.SOLUTION: A backup system includes a plurality of backup storage apparatuses for storing backup data of backup target data stored in a storage apparatus. The plurality of backup storage devices are classified as backup storage devices belonging to either the primary tier or the secondary tier. In a backup system, a storage apparatus stores primary backup data, which is backup data of data to be backed up, in a backup storage apparatus belonging to a primary tier, and the backup storage apparatus belonging to the primary tier stores secondary backup data, which is backup data of the primary backup data, in a backup storage apparatus belonging to a secondary tier, thereby backing up the data to be backed up.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a backup system and a backup method. [Background technology]

[0002] The 3-2-1 rule for backups is a common strategy for ensuring data safety. The 3-2-1 rule for backups consists of the following three points: (1) Have three copies. That is, have the original data and two backups. (2) Store the backup data on two different types of storage devices. (3) Store one backup offsite. Store at least one backup in a location physically separate from your current location.

[0003] By following this 3-2-1 backup rule, you can significantly reduce the risk of data loss.

[0004] Patent Document 1 discloses a backup system that can properly maintain database redundancy by selecting a backup site from multiple backup sites that meets specified conditions (maximum number of users and maximum usage volume related to the backup site's spare capacity), such as an operational policy indicating the priority of backup sites each having a standby database and current usage status, when a failure at the current site is detected, and automatically switching to that site.

[0005] Patent Document 2 discloses that a storage device establishes a connection between a volume (second volume) provided in the storage device and a volume (first volume) of a backup device, and remotely copies data of the second volume to the first volume, and in response to a copy setting command issued by the server, copies data equivalent to the data of the first volume to a volume (third volume) provided with free space in the backup device (=backing up backup data). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2017-102834 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-157145 Summary of the Invention [Problem to be solved by the invention]

[0007] The inventors of the present application are considering performing backup operations by allocating multiple backup data sets to multiple storage devices so as to adhere to predetermined allocation rules. In this case, due to a failure of a storage device or a poor connection between the storage devices, it may not be possible to adhere to the backup data allocation rules, and the robustness of the backup operation may not be maintained.

[0008] The present invention has been made to solve the above-mentioned problems. That is, one of the objects of the present invention is to provide a backup system and a backup method that can maintain the robustness of backup operations. [Means for solving the problem]

[0009] In order to solve the above problem, the backup system of the present invention is a backup system including a plurality of backup storage devices for storing backup data of data to be backed up stored in storage devices, wherein the plurality of backup storage devices are classified as backup storage devices belonging to either a primary tier or a secondary tier, and the storage devices store primary backup data, which is backup data of the data to be backed up, in the backup storage devices belonging to the primary tier, and the backup storage devices belonging to the primary tier store secondary backup data, which is backup data of the primary backup data, in the backup storage devices belonging to the secondary tier, thereby backing up the data to be backed up.

[0010] The backup method of the present invention is a backup method that uses a plurality of backup storage devices for storing backup data of data to be backed up that is stored in a storage device, and the plurality of backup storage devices are classified as backup storage devices belonging to either a primary tier or a secondary tier, and the storage devices store primary backup data, which is backup data of the data to be backed up, in the backup storage device belonging to the primary tier, and the backup storage device belonging to the primary tier stores secondary backup data, which is backup data of the primary backup data, in the backup storage device belonging to the secondary tier, thereby backing up the data to be backed up. [Effects of the Invention]

[0011] According to the present invention, the robustness of backup operations can be maintained. Note that the effects described herein are not necessarily limited to those described herein, and may be any of the effects described in this disclosure. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a backup system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing an example of the hardware configuration of a storage device. [Figure 3] FIG. 3 is a diagram for explaining the monitoring task table. [Figure 4] FIG. 4 is a diagram for explaining the condition table. [Figure 5] FIG. 5 is a diagram for explaining the backup table. [Figure 6] FIG. 6 is a diagram for explaining the BK location table. [Figure 7A] FIG. 7A is a diagram for explaining the storage tier table. [Figure 7B] FIG. 7B is a diagram for explaining the recovery task table. [Figure 8A] FIG. 8A is a diagram for explaining an outline of the operation of the backup system. [Figure 8B] FIG. 8B is a diagram for explaining an outline of the operation of the backup system. [Figure 8C] FIG. 8C is a diagram for explaining an outline of the operation of the backup system. [Figure 8D] FIG. 8D is a diagram for explaining an outline of the operation of the backup system. [Figure 9A] FIG. 9A is a flowchart showing the processing flow executed by the backup system. [Figure 9B] FIG. 9B is a flowchart showing the processing flow executed by the backup system. [Figure 10] FIG. 10 is a flowchart showing the flow of switching the backup destination device of the primary layer executed by the backup system. [Figure 11]FIG. 11 is a flowchart showing the flow of switching the backup destination device in the secondary layer, which is executed by the backup system. [Figure 12] FIG. 12 is a diagram for explaining the evaluation score table. [Figure 13A] FIG. 13A is a flowchart showing the flow of device switching processing in the primary layer executed by the backup system according to the second embodiment. [Figure 13B] FIG. 13B is a flowchart showing the flow of device switching processing in the primary layer executed by the backup system according to the second embodiment. [Figure 14A] FIG. 14A is a flowchart showing the flow of device switching processing in the secondary layer executed by the backup system according to the second embodiment. [Figure 14B] FIG. 14B is a flowchart showing the flow of device switching processing in the secondary layer executed by the backup system according to the second embodiment. [Figure 15] FIG. 15 is a flowchart showing the processing flow executed by the backup system according to the third embodiment. [Figure 16] FIG. 16 is a flowchart showing the flow of switching to the previous device. [Figure 17] FIG. 17 is a flowchart showing the processing flow executed by the backup system according to the third embodiment. [Figure 18] FIG. 18 is a flowchart showing the flow of switching to the previous device. [Figure 19A] FIG. 19A is a flowchart showing the processing flow executed by the backup system according to the fourth embodiment. [Figure 19B] FIG. 19B is a flowchart showing the processing flow executed by the backup system according to the fourth embodiment. [Figure 20A] FIG. 20A is a flowchart showing the processing flow executed by the backup system according to the fourth embodiment. [Figure 20B]FIG. 20B is a flowchart showing the processing flow executed by the backup system according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. In all the drawings of the embodiments, the same or corresponding parts may be denoted by the same reference numerals.

[0014] In the following description, various types of information may be described using expressions such as "table" and "record," but the various types of information may also be expressed using other data structures. When describing identification information, expressions such as "ID," "name," and "number" are used, but these are interchangeable and other expressions may also be used. In some cases, processing is described using a device or system as the subject, but the subject of the processing may be a processor, program, or controller instead of a device or system.

[0015] <<First Embodiment>> Figure 1 is a diagram showing an example of the configuration of a backup system according to a first embodiment of the present invention. As shown in Figure 1, the backup system includes hosts 100a to 100c, a first storage device 210, a second storage device 220, a third storage device 230, a fourth storage device 240, and a fifth storage device 250. Hereinafter, hosts 100a to 100c may be referred to as "hosts 100" when there is no need to particularly distinguish between them.

[0016] The host 100 is a computer (server device) that issues IO requests. The host 100 may be a physical computer or a virtual computer. The host 100 is connected to a first storage device 210 via a SAN (Storage Area Network) 110. The first storage device 210 includes a plurality of business volumes 211. The business volumes 211 are provided to the host 100 from the first storage device 210. The host 100 recognizes the business volumes 211 when the business volumes 211 are mounted on the host 100.

[0017] The second storage device 220 to the fifth storage device 250 are backup storage devices used to store backup data.

[0018] The second storage device 220 to the fifth storage device 250 are set (registered, classified) as storage devices belonging to either the primary tier or the secondary tier.

[0019] In a backup system, one storage device selected from the storage devices belonging to the primary tier and one storage device selected from the storage devices belonging to the secondary tier are associated with a storage device that holds (stores) the data to be backed up as the storage devices in which the backup data is stored. Note that the storage device that holds (stores) the data to be backed up and the storage device in which the backup data of the data to be backed up is sometimes referred to as "storage devices having a backup relationship" or "storage devices constituting a backup relationship."

[0020] A storage device that holds the data to be backed up sends a copy of the data to be backed up (hereinafter, sometimes referred to as "primary backup data") to a storage device that belongs to the primary tier with which it has a backup relationship, and stores the primary backup data in the storage device that belongs to the primary tier.

[0021] A storage device belonging to the primary tier sends a copy of the primary backup data (hereinafter, sometimes referred to as "secondary backup data") to a storage device belonging to the secondary tier with which it has a backup relationship, and stores the secondary backup data in a storage device belonging to the secondary tier.

[0022] 1, the second storage device 220 and the third storage device 230 are set (registered) as storage devices belonging to the primary tier. The fourth storage device 240 and the fifth storage device 250 are set (registered, classified) as storage devices belonging to the secondary tier. Note that the backup system may include one or more other storage devices other than the first storage device to the fifth storage device, and one or more other storage devices may be set (registered, classified) as storage devices belonging to either the primary tier or the secondary tier.

[0023] The second storage device 220 includes a volume 221a in which a full backup copy of the business volume 211 of the first storage device 210 is stored, and multiple volumes 221b in which differential backup data of areas updated since the previous full backup copy is stored. The backup data stored in volume 221a and the backup data stored in the multiple volumes 221b are backup data at different points in time. Backup data at different points in time can be called backup data of different generations. In the second storage device 220, a predetermined number of generations of backup data are stored in volumes prepared for each generation.

[0024] The fourth storage device 240 includes a volume 241a in which a full backup copy of volume 221a is stored, and a volume 241b in which a full backup copy of volume 221b is stored. The backup data stored in volume 241a and the backup data stored in the multiple volumes 241b are backup data at different times. In the fourth storage device 240, a predetermined number of generations of backup data are stored in volumes prepared for each generation.

[0025] 2 is a block diagram showing an example of the hardware configuration of a storage device 10. The storage device 10 in FIG. 2 corresponds to each of the first storage device 210 to the fifth storage device 250 in FIG.

[0026] The storage apparatus 10 has a plurality of (or one) physical storage devices (for example, drives such as SSDs (Solid State Drives) and HDDs (Hard Disk Drives)) called PDEVs 51, and a storage controller 52 connected to the PDEVs 51. The plurality of PDEVs 51 configure a plurality of volumes that are logical storage areas.

[0027] The storage controller 52 has an I / F 53, an I / F 54, two memories 55, and two processors 56 connected thereto.

[0028] The I / F 53 is a communication interface device that mediates the exchange of data between an external device (for example, the host 100, another storage device) and the storage controller 52. The first storage device 210 is connected to the host. The first storage device 210 is connected to the second storage device 220 and the third storage device 230. For example, the second storage device 220 is connected to the fourth storage device 240 and the fifth storage device 250. The third storage device 230 is connected to the fourth storage device 240 and the fifth storage device 250.

[0029] In addition, the host 100 connected to the storage device 10 sends an I / O request (write request or read request) to the storage controller 52 specifying the I / O destination (for example, a logical volume number such as a LUN (Logical Unit Number) or a logical address such as an LBA (Logical Block Address)).

[0030] The I / F 54 is a communication interface device that mediates the exchange of data between the multiple PDEVs 51 and the storage controller 52. The multiple PDEVs 51 are connected to the I / F 54.

[0031] The memory 55 stores programs executed by the processor 56 and data used by the processor 56. The processor 56 executes the programs stored in the memory 55. In this example, the set of the memory 55 and the processor 56 is duplicated.

[0032] The storage device 10 may be a storage device provided by a cloud service.

[0033] FIG. 3 is a diagram illustrating a monitoring task table 3000. The monitoring task table 3000 is stored in the first storage device 210. As shown in FIG. 3, the monitoring task table 3000 includes columns for storing information (values): #301, task ID 302, target 303, capacity 304, and related condition 305. In the monitoring task table 3000, information corresponding to each column related to a monitoring task is associated with each other and stored as row-based information (records). Specifically, #301 stores identification information assigned to row-based information (records). Task ID 302 stores the identification number (ID) of the task. Target 303 stores identification information of the volume to be monitored. Capacity 304 stores the capacity of the volume to be monitored. Related condition 305 stores the monitoring condition under which the monitoring task is invoked.

[0034] FIG. 4 is a diagram illustrating a condition table 4000. The condition table 4000 is stored in the first storage device 210. As shown in FIG. 4, the condition table 4000 includes columns (columns) for storing information (values): #401, content 402, type 403, task ID 404, and target 405. In the condition table 4000, information corresponding to each column related to a monitoring task is associated with each other and stored as row-based information (records). Specifically, #401 stores identification information assigned to row-based information (records). Content 402 stores the content of the condition when the monitoring task is invoked. Type 403 stores the type of condition when the monitoring task is invoked. Task ID 404 stores the identification number (ID) of the monitoring task to which the condition when the monitoring task is invoked is applied. Target 405 stores the identification number of the target volume to which the monitoring task is applied.

[0035] FIG. 5 is a diagram illustrating a backup table 5000. The backup table 5000 is stored in the first storage device 210. As shown in FIG. 5, the backup table 5000 includes columns for storing information (values): #501, target 502, item 503, value 504, and capacity reduction rate 505. In the backup table 5000, information corresponding to each column related to backup data is associated with each other and stored as row-based information (records). Specifically, #501 stores identification information assigned to row-based information (records). Target 502 stores identification information of the volume in which the original data to be backed up is stored. Item 503 stores the type of backup capacity. Value 504 stores the capacity of the backup data. Capacity reduction rate 505 stores the capacity reduction rate of the backup data when the capacity reduction function is used.

[0036] FIG. 6 is a diagram illustrating a BK location table 6000. The BK location table 6000 is stored in the first storage device 210. As shown in FIG. 6, the BK location table 6000 includes columns for storing information (values): #601, target 602, item 603, device ID 604, status 605, and BK related 606. In the BK location table 6000, information corresponding to each column regarding the storage tier and storage device where the backup data is located is associated with each other and stored as row-based information (records). Specifically, #601 stores identification information assigned to row-based information (records). Target 602 stores identification information of the volume where the original data to be backed up is stored. Item 603 stores the storage tier where the backup data is located. Device ID 604 stores the ID of the storage device where the backup data is stored. In this example, device ID 0001 indicates the first storage device 210, device ID 0002 indicates the second storage device 220, device ID 0003 indicates the third storage device 230, device ID 0004 indicates the fourth storage device 240, and device ID 0005 indicates the fifth storage device 250. Status 605 stores information indicating whether the backup data is normal. "Normal" indicates that the backup data is normal, and "Warning" indicates that the backup data is abnormal. BK related 606 stores the ID of the information (record) for each row in the backup table 5000.

[0037] FIG. 7A is a diagram illustrating a storage tier table 7000. The storage tier table 7000 is stored in the first storage device 210. As shown in FIG. 7A, the storage tier table 7000 includes the following columns for storing information (values): #701, device ID 702, registered tier 703, type 704, type 705, status 706, and related task 707. In the storage tier table 7000, information corresponding to each column related to a storage device is associated with each other and stored as row-based information (records). Specifically, #701 stores identification information for identifying row-based information (records). The device ID 702 stores the identification ID of the storage device. The registered tier 703 stores the storage tier to which the corresponding storage device belongs. The type 704 stores the type of the corresponding storage device. The type 705 stores the type of the storage device. On-premise indicates that the corresponding storage device is in an on-premise environment. Cloud indicates that the corresponding storage device is a storage device provided by a cloud service. Status 706 stores information indicating whether the status (including connection status) of the storage device is normal or not. Related Task 707 stores the ID of the corresponding monitoring task.

[0038] FIG. 7B is a diagram illustrating a recovery task table 7100. The recovery task table 7100 is stored in the first storage device 210. As shown in FIG. 7B, the recovery task table 7100 includes columns for storing information (values), such as #711, task ID 712, monitoring task ID 713, status 714, target 715, recovery layer 716, switching source 717, and switching destination 718. In the recovery task table 7100, information corresponding to each column related to the history of the recovery task is associated with each other and stored as information (records) on a row-by-row basis. Specifically, #711 stores identification information for identifying the information (record). The task ID 711 stores the identification ID of the recovery task. The monitoring task ID 713 stores the identification ID of the monitoring task. The status 714 stores information indicating whether the recovery was successful. The target 715 stores identification information of the volume to be backed up. The recovery layer 716 stores the storage layer for which the backup relationship has been restored. The switching source 717 stores identification information for the switching source storage device. The switching destination 718 stores identification information for the switching destination storage device.

[0039] <Summary> <Backup configuration> An overview of the present invention will be described. In the backup system, the second storage device 220 to the fifth storage device 250, in which backup data is arranged (stored), are set (registered, classified) as storage devices belonging to either the primary tier or the secondary tier. Typically, the storage devices belonging to the primary tier and the storage devices belonging to the secondary tier are set (registered, classified) so that they belong to storage devices located at different sites. Note that the storage devices belonging to the primary tier and the storage devices belonging to the secondary tier may also be set (registered, classified) so that they belong to storage devices located at the same site. Storage devices located at different sites may also be set (registered, classified) so that they belong to the same storage tier.

[0040] The backup system prepares multiple backup data for data to be backed up, allocates the multiple backup data in storage devices so that they comply with a placement rule, and manages the backup data in different storage devices. The placement rule is a rule that primary backup data is allocated to a primary tier storage device, and secondary backup data is allocated to a secondary tier storage device. The backup system allocates the backup data so that it complies with this placement rule, and performs backup operations so that the backup data maintains a state in which it complies with the placement rule, thereby achieving robust and highly available backup operations.

[0041] In the example shown in Fig. 8A, original data A to be backed up is arranged in the first storage device 210. The backup system arranges (stores) backup data BK01 and BK02 of the original data A (hereinafter, these may be referred to as "primary backup data BK") in the second storage device 220 of the primary tier, and arranges (stores) backup data BK01' and BK02' of the primary backup data BK of the original data A (hereinafter, these may be referred to as "secondary backup data BK'") in the fourth storage device 240 of the secondary tier.

[0042] In this example, the backup executed by the first storage device 210 is a full backup in which a copy of data A stored in the business volume 211 is sent to the backup destination primary tier storage device, and a differential backup in which a copy of data that has been changed or added to the initial backup data is sent to the backup destination. Backup data BK01 is full backup data of the business volume 211, and backup data BK02 is differential backup data of the business volume 211.

[0043] The backup executed by the second storage device 220 is a full backup in which copies of the backup data BK01 and the backup data BK02 are sent to the backup destination. The backup data BK01' and the backup data BK02' are full backup data of the backup data BK01 and the backup data BK02, respectively.

[0044] The backup system can achieve highly available backup operations by arranging the original data A, the primary backup data BK in the second storage device 220 in the primary tier, and the secondary backup data BK' in the fourth storage device 240 in the secondary tier in a relationship (1:1:1 relationship) where they are located in storage devices belonging to three different tiers. By replicating and managing the same backup data for each storage tier, the backup system avoids the risk of data loss due to device failure or the loss of backup data due to security risks such as viruses.

[0045] Primary backup data BK of data A in the business volume 211 is stored in volume 221a (221b) of the second storage device 220 belonging to the primary tier by the first storage device 210. The primary backup data BK stored in the second storage device 220 belonging to the primary tier is backup data intended to protect data A stored in the business volume 211 that is the backup target.

[0046] Secondary backup data BK', which is backup data of the primary backup data BK in volume 221a (221b), is stored in volume 241a (241b) of the fourth storage device 240 belonging to the secondary tier by the second storage device 220 belonging to the primary tier. The secondary backup data BK' stored in the fourth storage device 240 belonging to the secondary tier is backup data intended to protect the primary backup data BK.

[0047] A first storage device 210 having an operation volume 211 transmits primary backup data BK of data A to be backed up to a second storage device 220 belonging to the primary tier and stores it in a volume 221a (221b).

[0048] The second storage device 220 transmits the secondary backup data BK', which is backup data of the primary backup data BK, to the fourth storage device 240 belonging to the secondary tier and stores it in the volume 241a (241b).

[0049] In this way, the first storage device 210 stores primary backup data BK in the second storage device 220, and the second storage device 220 stores secondary backup data BK' in the fourth storage device 240. This prevents one storage device from performing scheduled backups (data copies) of original data to multiple devices, thereby reducing the possibility of heavy IO load on the backup system. Furthermore, the backup system minimizes access to the original data to minimize load, thereby avoiding 1:N backup operations. In other words, each storage device in a backup relationship can perform backup operations by accessing only one storage device, thereby avoiding 1:N backup operations in which one storage device accesses multiple storage devices.

[0050] <Monitoring process, recovery process> In the operation of a backup system, due to a failure of a storage device or a poor connection between storage devices, it may become impossible to maintain the backup data placement rules for the data to be backed up on the storage devices, which place primary backup data in the primary tier storage device and secondary backup data in the secondary tier storage device.

[0051] Therefore, the backup system monitors whether the backup data placement rules can be maintained. If a situation arises in which the backup data placement rules cannot be maintained, the backup system switches the storage device in which the backup data is placed so that the backup data placement rules can be maintained, and restores the backup data so that the backup data is placed in the storage device after the switch.

[0052] A specific example will be given below.

[0053] In the backup system shown in FIG. 8A, for data A to be backed up in the first storage device 210, primary backup data BK is placed in the second storage device 220 in the primary tier, and secondary backup data BK' is placed in the fourth storage device 240 in the secondary tier.

[0054] In the backup system, the first storage device 210 monitors the connection status between the first storage device 210 and the second storage device 220, and monitors the connection status between the second storage device 220 and the fourth storage device 240.

[0055] S801 (FIG. 8A): A connection failure occurs between the first storage device 210 and the second storage device 220.

[0056] S802 (FIG. 8B): The first storage device 210 selects a third storage device 230 that can be used in place of the second storage device 220 from among the storage devices belonging to the primary tier.

[0057] S803 (FIG. 8B): The third storage device 230 selects the fourth storage device 240 that can restore the primary backup data BK to the third storage device 230 from among the secondary tier storage devices.

[0058] S804 (FIG. 8B): The fourth storage device 240 sends a copy of the secondary backup data BK′ to the third storage device 230, and restores the primary backup data BK in the third storage device 230.

[0059] S805 (FIG. 8B): The switchover from the second storage device 220 to the third storage device 230 is completed. Thereafter, the backup system performs a backup of data A to be backed up in the first storage device 210 in the original tier by allocating primary backup data BK in the third storage device 230 in the primary tier and secondary backup data BK' in the fourth storage device 240 in the secondary tier while adhering to the allocation rules.

[0060] In the backup system shown in Figure 8C, for data A to be backed up in the first storage device 210, primary backup data BK is placed in the second storage device 220 in the primary tier, and secondary backup data BK' is placed in the fourth storage device 240 in the secondary tier.

[0061] In the backup system, the first storage device 210 monitors the connection status between the first storage device 210 and the second storage device 220, and monitors the connection status between the second storage device 220 and the fourth storage device 240.

[0062] S811 (FIG. 8C): A connection failure occurs between the second storage device 220 and the fourth storage device 240.

[0063] S812 (FIG. 8D): The second storage device 220 selects a fifth storage device 250 that can be used in place of the fourth storage device 240 from among the storage devices belonging to the secondary tier.

[0064] S813 (FIG. 8D): The fifth storage device 250 selects the second storage device 220 that can restore the primary backup data BK to the fifth storage device 250 from among the storage devices in the primary tier.

[0065] S814 (FIG. 8D): The second storage device 220 sends a copy of the primary backup data BK to the fifth storage device 250, and restores the secondary backup data BK′ in the fifth storage device 250.

[0066] S815 (FIG. 8D): The switchover from the fourth storage device 240 to the fifth storage device 250 is completed. For data A to be backed up in the first storage device 210, the backup system allocates primary backup data BK in the second storage device 220 in the primary tier, and allocates secondary backup data BK' in the fifth storage device 250 in the secondary tier, thereby backing up data A while adhering to the allocation rules.

[0067] As described above, the backup system monitors whether the storage device is in a state where it can observe the backup data placement rules, and if it is unable to maintain a state where it can observe the backup data placement rules due to a poor connection to the storage device or the like, it switches the storage device where the backup data is placed so that it can maintain a state where it can observe the backup data placement rules, and restores the backup data so that it is placed in the storage device to which it is switched.

[0068] This enables the backup system to achieve highly available backup operations by maintaining a relationship (1:1:1 relationship) in which the data to be backed up and the backup data are placed on storage devices belonging to three different tiers.

[0069] <Specific operation> 9A and 9B are flowcharts showing the monitoring process flow executed by the backup system. The backup system starts the process from step 900 in FIG.

[0070] Step 905: The first storage device 210 checks the state of the original data (original data A in this example) in the first storage device 210 that constitutes the backup relationship.

[0071] Step 910: The first storage device 210 determines whether the state of the original data is normal. If the state of the original data is not normal, the first storage device 210 determines "NO" and proceeds to step 915. If the state of the original data is normal, the first storage device 210 determines "YES" and proceeds to step 920.

[0072] Step 915: The first storage device 210 notifies other devices (such as the host 100) of an alert of the abnormal state of the backup relationship of the target data A (original data A).

[0073] Step 920: The first storage device 210 refers to the BK location table 6000 in Figure 6 and the storage tier table 7000 in Figure 7A, and checks the backup status of the primary tier storage devices that make up the backup relationship (information about the primary tier storage devices, secondary tier storage devices, and backup data).

[0074] Step 925: The first storage device 210 determines whether the connection with the storage device belonging to the primary tier that configures the backup relationship is normal, based on the status of the storage tier table 7000 in FIG. 7A. In this example, the first storage device 210 determines whether the connection with the second storage device 220 that belongs to the primary tier in which the primary backup data BK of the original data A is stored is normal. If the connection is not normal, the first storage device 210 determines "NO" and proceeds to step 930, where it proceeds to the recovery process (the flow for switching the backup destination device of the primary tier in FIG. 10, which will be described later). If the connection is normal, the first storage device 210 determines "YES" and proceeds to step 935.

[0075] Step 935: The first storage device 210 references the BK location table 6000 in FIG. 6 and determines whether the status of the primary backup data BK is normal. If the status of the primary backup data BK is not normal, the first storage device 210 determines "NO" and proceeds to step 940, where the second storage device 220 restores the primary backup data BK. In step 940, the second storage device 220 in the primary tier obtains secondary backup data BK' corresponding to the abnormal primary backup data BK from the fourth storage device 240 in the secondary tier and restores the primary backup data BK from the secondary backup data BK'. Note that, when the second storage device 220 in the primary tier restores the primary backup data BK, it sends update information to the first storage device 210, and the first storage device 210 changes the status corresponding to the restored primary backup data BK in the BK location table 6000 in FIG. 6 to normal. Thereafter, the second storage device 220 in the primary tier returns to step 935. If the status of the primary backup data BK is normal, the first storage device 210 determines “YES” and proceeds to step 945 .

[0076] Step 945: The second storage device 220 belonging to the primary tier updates the operational status of the backup-related primary tier storage devices (information on the primary tier storage devices, secondary tier storage devices and backup data), and proceeds to step 950 in Figure 9B.

[0077] Step 950: The first storage device 210 refers to the BK location table 6000 in Figure 6 and the storage tier table 7000 in Figure 7A, and checks the backup status (information regarding the primary tier storage device, secondary tier storage device, and backup data) of the secondary tier storage device (in this example, the fourth storage device 240) that constitutes the backup relationship.

[0078] Step 955: The first storage device 210 determines whether the connection between the storage device belonging to the primary tier and the storage device belonging to the secondary tier that constitute the backup relationship is normal, based on the status of the storage tier table 7000 in FIG. 7A. In this example, the first storage device 210 determines whether the connection between the second storage device 220 belonging to the primary tier in which the primary backup data BK of the original data A is stored and the fourth storage device 240 belonging to the secondary tier in which the secondary backup data BK' is stored is normal. If the connection is not normal, the first storage device 210 determines "NO" and proceeds to step 960, where it proceeds to the recovery process (the flow for switching the backup destination device in the secondary tier in FIG. 11, which will be described later). If the connection is normal, the first storage device 210 determines "YES" and proceeds to step 965.

[0079] Step 965: The first storage device 210 references the BK location table 6000 in FIG. 6 and determines whether the status of the secondary backup data BK' is normal. If the status of the secondary backup data BK' is not normal, the first storage device 210 determines "NO" and proceeds to step 970, where the fourth storage device 240 in the secondary tier restores the secondary backup data BK'. In step 970, the fourth storage device 240 in the secondary tier obtains primary backup data BK corresponding to the abnormal secondary backup data BK' from the second storage device 220 in the primary tier and restores the secondary backup data BK' from the primary backup data BK. Note that, after restoring the secondary backup data BK', the fourth storage device 240 in the secondary tier sends update information to the first storage device 210, and the first storage device 210 changes the status corresponding to the restored secondary backup data BK' in the BK location table 6000 in FIG. 6 to normal. Thereafter, the fourth storage device 240 belonging to the secondary tier returns to step 965. If the status of the secondary backup data BK' is normal, the first storage device 210 determines "YES" and proceeds to step 975.

[0080] Step 975: The fourth storage device 240 belonging to the secondary tier updates the operational status of the backup-related secondary tier storage devices (information on the primary tier storage devices, secondary tier storage devices and backup data).

[0081] Step 980: The fourth storage device 240 belonging to the secondary tier sends information about the backup data of the fourth storage device 240 belonging to the secondary tier of the backup relationship to the second storage device 220 belonging to the primary tier.

[0082] Step 985: The second storage device 220 belonging to the primary tier sends to the first storage device 210 information regarding the backup data of the storage device belonging to the primary tier of the backup relationship and information regarding the backup data of the storage device belonging to the secondary tier.

[0083] Step 990: The first storage device 210 updates all backup-related operational status information (information relating to the primary tier storage device, the secondary tier storage device and backup data).

[0084] Step 995: The backup system temporarily ends this processing flow.

[0085] 10 is a flowchart showing the flow of switching the backup destination device of the primary tier executed by the backup system. The backup system starts processing from step 1000 in FIG.

[0086] Step 1005: The first storage device 210 checks the storage devices belonging to the connectable primary tier and the free data capacity of the storage devices belonging to the primary tier. Note that a storage device that can be connected to the first storage device 210 and has free capacity that can store backup data becomes a switchable storage device.

[0087] Step 1010: The first storage device 210 determines whether or not there is a storage device belonging to the switchable primary tier. If there is no storage device belonging to the switchable primary tier, the first storage device 210 determines "NO" and proceeds to step 1015, where it notifies another device (such as the host 100) of an alert related to the backup of the target data A (original data A). Thereafter, the first storage device 210 proceeds to step 1095, and temporarily ends this processing flow.

[0088] If there is a storage device belonging to the switchable primary tier, the first storage device 210 determines "YES" and proceeds to step 1020. In this example, the subsequent processing will be explained assuming that the third storage device 230 exists as a storage device belonging to the switchable primary tier.

[0089] Step 1020: The third storage device 230 checks for connectable secondary tier storage devices.

[0090] Step 1025: The third storage device 230 determines whether or not there is a secondary tier storage device with which a relationship has been established (after backup settings for backing up data of the third storage device 230 have been completed). If there is no secondary tier storage device with which a relationship has been established, the third storage device 230 determines "NO" and proceeds to step 1030. If there is a secondary tier storage device with which a relationship has been established, the third storage device 230 determines "YES" and proceeds to step 1040. Note that in this example, the subsequent processing will be explained assuming that the fourth storage device 240 exists as a storage device belonging to the secondary tier with which a relationship has been established.

[0091] Step 1030: The third storage device 230 sends a notification to the first storage device 210 that stores the target data A that the third storage device 230 in the primary tier cannot be switched.

[0092] Step 1035 : The first storage device 210 issues an alert related to the backup of the target data A, and proceeds to step 1095 .

[0093] Step 1040: The third storage device 230 sends a command to restore the backup data to the fourth storage device 240 in the secondary tier.

[0094] Step 1045: The fourth storage device 240 copies the secondary backup data BK' in the secondary tier to the third storage device 230 in the primary tier, and the third storage device 230 restores the primary backup data BK from the copy of the secondary backup data BK'. Note that restoring also includes using the copy as the primary backup data BK as is.

[0095] Step 1050: The third storage device 230 updates the operational status of the backup-related primary tier storage devices (information on the primary tier storage devices, secondary tier storage devices and backup data).

[0096] Step 1055: The third storage device 230 sends information about the backup data of the third storage device 230 belonging to the primary tier of the backup relationship to the first storage device 210 where the original data A is stored.

[0097] Step 1060: The first storage device 210 updates all backup-related operational status information (information regarding the primary tier storage device, secondary tier storage device, and backup data) based on the information received from the third storage device 230 in the primary tier.

[0098] Step 1065 : The first storage device 210 creates execution information for the backup-related recovery process, and stores it in the recovery task table 7100 .

[0099] Step 1095: The backup system temporarily ends this processing flow.

[0100] 11 is a flowchart showing the flow of switching the backup destination device in the secondary tier executed by the backup system. The backup system starts processing from step 1100 in FIG.

[0101] Step 1105: The second storage device 220 checks the storage devices belonging to the connectable secondary tier and the free data capacity of the storage devices belonging to the secondary tier. Note that a storage device that can be connected to the second storage device 220 and has free capacity sufficient to store backup data becomes a switchable storage device.

[0102] Step 1110: The second storage device 220 determines whether or not there is a storage device belonging to a switchable secondary tier. If there is no storage device belonging to a switchable secondary tier, the second storage device 220 determines "NO" and proceeds to step 1115, where it notifies another device (such as the host 100) of an alert related to the backup of the target data A. The second storage device 220 then proceeds to step 1195, and temporarily ends this processing flow.

[0103] If there is a storage device belonging to the switchable secondary tier, the second storage device 220 judges "YES" and proceeds to step 1120. In this example, it is assumed that the fifth storage device 250 exists as a storage device belonging to the switchable secondary tier, and the subsequent processing will be explained.

[0104] Step 1120: The fifth storage device 250 checks for connectable primary tier storage devices.

[0105] Step 1125: The fifth storage device 250 determines whether or not there is a primary tier storage device with which a relationship has been established (after backup settings have been completed to back up data to the fifth storage device 250). If there is no primary tier storage device with which a relationship has been established, the fifth storage device 250 determines "NO" and proceeds to step 1130. If there is a primary tier storage device with which a relationship has been established, the fifth storage device 250 determines "YES" and proceeds to step 1140. Note that in this example, the subsequent processing will be explained assuming that the second storage device 220 exists as a storage device belonging to the primary tier with which a relationship has been established.

[0106] Step 1130: The fifth storage device 250 sends a notification to the first storage device 210 that stores the target data A that the fifth storage device 250 in the secondary tier cannot be switched.

[0107] Step 1135 : The first storage device 210 issues an alert related to the backup of the target data A, and proceeds to step 1195 .

[0108] Step 1140: The fifth storage device 250 sends a command to restore the backup data to the second storage device 220 in the primary tier.

[0109] Step 1145: The second storage device 220 copies the primary backup data BK in the primary tier to the fifth storage device 250 in the secondary tier, and the fifth storage device 250 restores secondary backup data BK' from the copy of the primary backup data BK. Note that restoring also includes using the copy as the secondary backup data BK' as is.

[0110] Step 1150: The fifth storage device 250 updates the operational status of the backup-related secondary tier storage devices (information on the primary tier storage devices, secondary tier storage devices and backup data).

[0111] Step 1155: The fifth storage device 250 transmits information about the backup data of the fifth storage device 250 belonging to the secondary tier of the backup relationship to the first storage device 210 where the original data A is stored.

[0112] Step 1160: The first storage device 210 updates all backup-related operational status information (information regarding the primary tier storage device, secondary tier storage device and backup data) based on the information received from the fifth storage device 250 in the secondary tier.

[0113] Step 1165 : The first storage device 210 creates execution information for the backup-related recovery process, and stores it in the recovery task table 7100 .

[0114] Step 1195: The backup system temporarily ends this processing flow.

[0115] <Effects> As described above, the backup system according to the first embodiment of the present invention can achieve robust and highly available backup operations by maintaining a relationship (1:1:1 relationship) in which the data to be backed up and the backup data are placed in storage devices belonging to three different tiers.

[0116] <<Second embodiment>> A backup system according to a second embodiment of the present invention will now be described. The backup system according to the second embodiment of the present invention differs from the backup system according to the first embodiment only in the following respects.

[0117] In the case where the backup data placement rules cannot be observed and it becomes necessary to switch storage devices that constitute a backup relationship, the backup system according to the second embodiment calculates an operation score for evaluating the operation status of the storage devices, selects a storage device with a superior operation score based on the operation score, and switches to the selected storage device. This allows the backup system to perform backup operations efficiently.

[0118] The following description will focus on this difference.

[0119] FIG. 12 is a diagram illustrating the evaluation score table 1200. The evaluation score table 1200 is stored in the first storage device 210. As shown in FIG. 12, the evaluation score table 1200 includes columns (columns) for storing information (values), such as #1201, device ID 1202, item 1203, and value 1204. In the evaluation score table 1200, information corresponding to each column required for calculating the operation score of a storage device is associated with each other and stored as row-based information (records). Specifically, #1201 stores identification information assigned to row-based information (records). Device ID 1202 stores the ID of the storage device. Item 1203 stores an item of information for calculating the evaluation score. Value 1204 stores the value of the corresponding item.

[0120] The backup system calculates the operation score based on the evaluation score table 1200 and the backup table 5000 as follows: operation score frc(s) = (predicted capacity consumption score) x w1 (priority weight) + (total operation cost) x w2 (priority weight). In the calculation formula, the predicted capacity consumption score is calculated as follows: predicted capacity consumption score = {(full backup capacity + differential backup capacity)} x capacity reduction rate (%), and total operation cost (yen / month) = estimated capacity cost + estimated I / O cost. The smaller the operation score, the better the evaluation.

[0121] Figures 13A and 13B are flowcharts showing the flow of device switching processing for the primary tier executed by the backup system according to the second embodiment. The flowcharts of Figures 13A and 13B differ from the flowchart of Figure 10 only in that steps 1020 to 1035 have been deleted and steps 1315 to 1335 have been added between steps 1010 and 1040. Therefore, the following explanation will focus on these differences.

[0122] In the second implementation tier, the backup system includes a plurality of storage devices other than the first storage device 210 to the fifth storage device 250. The primary tier includes a plurality of storage devices other than the second storage device 220 and the third storage device 230. The secondary tier includes a plurality of storage devices other than the fourth storage device 240 and the fifth storage device 250.

[0123] If there is a storage device belonging to the switchable primary tier in step 1010, the first storage device 210 determines "YES" and proceeds to step 1315. In this example, there are multiple storage devices, including the third storage device 230, that belong to the switchable primary tier.

[0124] Step 1315: The first storage device 210 acquires information about storage devices belonging to the primary tier that can be connected (switched) from the evaluation score table 1200 and the backup table 5000.

[0125] Step 1320: Based on the information about the storage device acquired in step 1315, the first storage device 210 calculates the operational score of the switchable storage device.

[0126] Step 1325: The first storage device 210 determines the storage device having the smallest operational score calculated from among the storage devices belonging to the primary tier as the switching destination.

[0127] Step 1330: The first storage device 210 determines whether the connection status between the switching destination storage device and the storage device belonging to the secondary tier is normal. If the connection status between the switching destination storage device and the storage device belonging to the secondary tier is not normal, the first storage device 210 determines "NO" in step 1330 and proceeds to step 1335. If the connection status between the switching destination storage device and the storage device belonging to the secondary tier is normal, the first storage device 210 determines "YES" in step 1330 and proceeds to the above-mentioned step 1040. Note that in this example, the subsequent processing will be explained assuming that the third storage device 230 is selected as the switchable storage device belonging to the primary tier with the smallest (best) operational score. Thereafter, the backup system executes the processing from step 1040 to step 1065 described above, then proceeds to step 1395 and temporarily ends this processing flow.

[0128] Step 1335: The first storage device 210 calculates the operational scores from the remaining switchable storage devices other than the switching destination storage device determined in step 1325, and proceeds to step 1325 again to determine the storage device with the smallest operational score calculated from the remaining switchable storage devices as the switching destination. Thereafter, the storage device proceeds to step 1330 and executes the processing of step 1330 described above.

[0129] Figures 14A and 14B are flowcharts showing the secondary tier device switching processing flow executed by the backup system according to the second embodiment. The flowcharts in Figures 14A and 14B differ from the flowchart in Figure 11 only in that steps 1120 to 1135 have been deleted and steps 1415 to 1435 have been added between steps 1110 and 1140. Therefore, the following explanation will focus on these differences.

[0130] If there is a storage device belonging to the switchable secondary tier in step 1110, the second storage device 220 determines "YES" and proceeds to step 1415. In this example, there are multiple storage devices, including the fifth storage device 250, that belong to the switchable secondary tier.

[0131] Step 1415: The second storage device 220 acquires information about storage devices belonging to the secondary tier that can be connected (switched) from the evaluation score table 1200 and the backup table 5000.

[0132] Step 1420: Based on the information about the storage device acquired in step 1415, the second storage device 220 calculates the operational score of the switchable storage device.

[0133] Step 1425: The second storage device 220 determines the storage device having the smallest operational score calculated from among the storage devices belonging to the secondary tier as the switching destination.

[0134] Step 1430: The second storage device 220 determines whether the connection status between the switching destination storage device and the storage device belonging to the primary tier is normal. If the connection status between the switching destination storage device and the storage device belonging to the primary tier is not normal, the second storage device 220 determines "NO" in step 1430 and proceeds to step 1435. If the connection status between the switching destination storage device and the storage device belonging to the primary tier is normal, the second storage device 220 determines "YES" in step 1430 and proceeds to the above-mentioned step 1140. Note that in this example, the subsequent processing will be explained assuming that the fifth storage device 250 is selected as the switchable storage device belonging to the secondary tier with the best (smallest) operational score. Thereafter, the backup system executes the processing of the above-mentioned steps 1140 to 1165, then proceeds to step 1495 and temporarily ends this processing flow.

[0135] Step 1435: The second storage device 220 calculates the operational scores from the remaining switchable storage devices other than the switching destination storage device determined in step 1425, and proceeds to step 1425 again to determine the storage device with the smallest operational score calculated from the remaining switchable storage devices as the switching destination. Thereafter, the second storage device 220 proceeds to step 1430 and executes the processing of step 1430 described above.

[0136] <Effects> As described above, the backup system according to the second embodiment of the present invention has the same effects as those of the first embodiment. Furthermore, the backup system according to the second embodiment of the present invention can perform backup operations efficiently.

[0137] <<Third Embodiment>> A backup system according to a third embodiment of the present invention will now be described. The backup system according to the third embodiment of the present invention differs from the backup system according to the first embodiment only in the following respects.

[0138] In the backup system of the third embodiment, when a switchover of a storage device in the primary tier and / or a storage device in the secondary tier is performed, during execution of the monitoring process, it monitors whether the storage devices that constitute the backup relationship can be returned from the storage device after the switchover to the storage device before the switchover.

[0139] If a path can actually be established with the device before the switchover, or with the device in the primary or secondary layer because the connection has been restored, the monitoring process attempts to restore the storage device that constitutes the backup relationship.

[0140] The following description will focus on this difference.

[0141] Fig. 15 is a flowchart showing the processing flow executed by the backup system. The backup system starts processing from step 1500 in Fig. 15 and proceeds to step 1505. In this example, the storage device before switching is the second storage device 220, and the storage device after switching is the third storage device 230.

[0142] Step 1505: The first storage device 210 refers to the recovery task table 7100 in FIG. 7B, and checks the execution history of the recovery process for the backup relationship.

[0143] Step 1510: The first storage device 210 determines whether or not the connection with the storage device before switching is normal. If the connection with the storage device before switching is not normal, the first storage device 210 determines "NO" and proceeds to step 1595, temporarily terminating this processing flow. If the connection with the storage device before switching is normal, the first storage device 210 determines "YES" and proceeds to step 1515.

[0144] Step 1515: The first storage device 210 determines whether the status of the backup data in the storage device before switching is normal. If the status of the backup data in the storage device before switching is not normal, the first storage device 210 determines "NO" and proceeds to step 1595, temporarily terminating this processing flow. If the status of the backup data in the storage device before switching is normal, the first storage device 210 determines "YES" and proceeds to step 1520.

[0145] Step 1520: The first storage device 210 calculates the operational scores of the storage device before switching and the storage device after switching based on the evaluation score table 1200 and the backup table 5000.

[0146] Step 1525: The first storage device 210 determines whether the operation score of the storage device before switching is smaller than the operation score of the storage device after switching. If the operation score of the storage device before switching is equal to or greater than the operation score of the storage device after switching, the first storage device 210 determines "NO" and proceeds to step 1595, where it temporarily ends this processing flow.

[0147] If the operational score of the storage device before switching is lower than the operational score of the storage device after switching, the first storage device 210 judges "YES" and proceeds to step 1530, executes the recovery process of Figure 16 (switching flow to the device before switching), and then proceeds to step 1595 and temporarily ends this processing flow.

[0148] 16 is a flowchart showing the flow of switching back to the device before switching. The backup system starts processing from step 1600 and executes the processing from step 1605 to step 1645 described below, and then proceeds to step 1695 to temporarily end this processing flow.

[0149] Step 1605: The first storage device 210 acquires information about the backup data of the storage device after switching.

[0150] Step 1610: The first storage device 210 acquires information about the backup data of the storage device before switching.

[0151] Step 1615: The first storage device 210 determines the latest backup data to be adopted.

[0152] Step 1620: The second storage device 220 acquires backup data from the secondary tier storage device for which switching has not yet been performed.

[0153] Step 1625: The second storage device 220 creates backup data to be finally stored from the difference between the acquired backup data and the latest backup data.

[0154] Step 1630: The second storage device 220 updates the operation status of the second storage device 220 after the switch (after returning to the device before the switch).

[0155] Step 1635: The second storage device 220 transmits the backup information after the switch (after returning to the device before the switch) to the storage device of the original data (the first storage device 210).

[0156] Step 1640: The first storage device 210 updates all backup-related operational status information (information relating to the primary tier storage device, the secondary tier storage device and backup data).

[0157] Step 1645 : The first storage device 210 creates execution information for the backup-related recovery process, and stores it in the recovery task table 7100 .

[0158] Fig. 17 is a flowchart showing the processing flow executed by the backup system. The backup system starts processing from step 1700 in Fig. 17 and proceeds to step 1705. In this example, an example will be described in which the storage device before switching is the fourth storage device 240 and the storage device after switching is the fifth storage device 250.

[0159] Step 1705: The first storage device 210 refers to the recovery task table 7100 in FIG. 7B, and checks the execution history of the recovery process for the backup relationship.

[0160] Step 1710: The first storage device 210 determines whether the connection between the second storage device 220 and the storage device before switching is normal. If the connection between the second storage device 220 and the storage device before switching is not normal, the first storage device 210 determines "NO" and proceeds to step 1795, temporarily terminating this processing flow. If the connection between the second storage device 220 and the storage device before switching is normal, the first storage device 210 determines "YES" and proceeds to step 1715.

[0161] Step 1715: The first storage device 210 determines whether the status of the backup data in the storage device before switching is normal. If the status of the backup data in the storage device before switching is not normal, the first storage device 210 determines "NO" and proceeds to step 1795, temporarily terminating this processing flow. If the status of the backup data in the storage device before switching is normal, the first storage device 210 determines "YES" and proceeds to step 1720.

[0162] Step 1720: The second storage device 220 calculates the operational scores of the storage device before switching and the storage device after switching based on the evaluation score table 1200 and the backup table 5000.

[0163] Step 1725: The second storage device 220 determines whether the operation score of the storage device before switching is smaller than the operation score of the storage device after switching. If the operation score of the storage device before switching is equal to or greater than the operation score of the storage device after switching, the second storage device 220 determines "NO" and proceeds to step 1795, where it temporarily ends this processing flow.

[0164] If the operational score of the storage device before switching is lower than the operational score of the storage device after switching, the second storage device 220 judges "YES" and proceeds to step 1730, executes the recovery process of Figure 18 (switching flow to the device before switching), and then proceeds to step 1795 and temporarily ends this processing flow.

[0165] 18 is a flowchart showing the flow of switching back to the device before switching. The backup system starts processing from step 1800 and executes the processing from step 1805 to step 1845 described below, and then proceeds to step 1895 to temporarily end this processing flow.

[0166] Step 1805: The second storage device 220 acquires information about the backup data of the storage device after switching.

[0167] Step 1810: The second storage device 220 acquires information about the backup data of the storage device before switching.

[0168] Step 1815: The second storage device 220 determines the latest backup data to be adopted.

[0169] Step 1820: The fourth storage device 240 acquires backup data from the storage device in the primary tier for which switching has not yet been performed.

[0170] Step 1825: The fourth storage device 240 creates backup data to be finally stored from the difference between the acquired backup data and the latest backup data.

[0171] Step 1830: The fourth storage device 240 updates the operation status of the fourth storage device 240 after the switch (after returning to the device before the switch).

[0172] Step 1835: The fourth storage device 240 transmits the backup information after the switch (after returning to the device before the switch) to the first storage device 210.

[0173] Step 1840: The first storage device 210 updates all backup-related operational status information (information relating to the primary tier storage device, the secondary tier storage device and backup data).

[0174] Step 1845 : The first storage device 210 creates execution information for the backup-related recovery process, and stores it in the recovery task table 7100 .

[0175] <Effects> As described above, the backup system according to the third embodiment of the present invention achieves the same effects as those of the first embodiment. Furthermore, the backup system according to the third embodiment of the present invention can efficiently perform backup operations by returning the storage devices forming the backup relationship to the storage devices before the switch based on the operation score.

[0176] <<Fourth Embodiment>> A backup system according to a fourth embodiment of the present invention will now be described. The backup system according to the fourth embodiment of the present invention differs from the backup system according to the first embodiment only in the following respects.

[0177] The backup system according to the fourth embodiment monitors the operational status of the primary tier storage device and the secondary tier storage device, and optimizes the storage devices (primary tier storage device and secondary tier storage device) that constitute the backup relationship.

[0178] The following description will focus on this difference.

[0179] 19A and 19B are flowcharts showing the process flow executed by the backup system. The backup system starts processing from step 1900 in FIG.

[0180] Step 1905: The first storage device 210 calculates the operational scores of the storage device belonging to the primary tier and the storage device belonging to the secondary tier from the latest operational status of the backup relationship.

[0181] Step 1910: The first storage device 210 determines whether or not there is a storage device belonging to the primary tier of a connectable switching candidate. If there is no storage device belonging to the primary tier of a connectable switching candidate, the first storage device 210 determines "NO" and proceeds to step 1915. If there is a storage device belonging to the primary tier of a connectable switching candidate, the first storage device 210 determines "YES" and proceeds to step 1725.

[0182] Step 1915: The second storage device 220 determines whether or not there is a storage device belonging to the secondary tier that is a connectable switching candidate. If there is no storage device belonging to the secondary tier that is a connectable switching candidate, the second storage device 220 determines "NO" and proceeds to step 1995. If there is a storage device belonging to the secondary tier that is a connectable switching candidate, the second storage device 220 determines "YES" and proceeds to step 1920, and proceeds to the device switching flow for the secondary tier shown in Figures 20A and 20B, which will be described later.

[0183] Step 1925: The first storage device 210 acquires information about connectable primary tier storage devices.

[0184] Step 1930: The first storage device 210 calculates the operation score of the switchable storage device. The first storage device 210 calculates the operation score as follows, based on the evaluation score table 1200 and the backup table 5000: operation score fop(s) = (predicted capacity consumption score) × w1 (priority weight) + (actual operation cost) × w2 (priority weight). In the calculation formula, the predicted capacity consumption score is calculated as follows: predicted capacity consumption score = {(full backup capacity + differential backup capacity)} × capacity reduction rate (%), the total operation cost is calculated as follows: total operation cost (yen / month) = estimated capacity cost + estimated I / O cost, and the actual operation cost is calculated as follows: actual operation cost (yen / month) = actual capacity cost + actual I / O cost.

[0185] Step 1935: The first storage device 210 determines the storage device having the smallest value of the calculated operation scores, including the operation score of the storage device currently in operation, as the switching destination.

[0186] Step 1940: The first storage device 210 determines whether the connection between the switching destination storage device and the secondary tier storage device is normal. If the connection between the switching destination storage device and the secondary tier storage device is not normal, the first storage device 210 determines "NO" and proceeds to step 1945. If the connection between the switching destination storage device and the secondary tier storage device is normal, the first storage device 210 determines "YES" and proceeds to step 1950 in Figure 19B.

[0187] Step 1945: The first storage device 210 calculates the operational scores from the remaining switchable storage devices other than the switching destination storage device determined in step 1925, and proceeds to step 1935 again to determine the storage device (in this example, the third storage device 230) having the smallest operational score calculated from the remaining switchable storage devices as the switching destination. Thereafter, the storage device proceeds to step 1940 and executes the processing of step 1940 described above.

[0188] Step 1950: The third storage device 230 sends a backup data restoration instruction to the secondary tier storage device (the fourth storage device 240 in this example).

[0189] Step 1955: The fourth storage device 240 copies the backup data of the secondary tier to the storage device of the primary tier (the third storage device 230 in this example).

[0190] Step 1960: The third storage device 230 updates the operational status of the primary tier storage device in the backup relationship.

[0191] Step 1965: The third storage device 230 sends information about the backup data of the third storage device 230 belonging to the primary tier of the backup relationship (information about the primary tier storage device, secondary tier storage device and backup data) to the first storage device 210 where the original data A is stored.

[0192] Step 1970: The first storage device 210 updates all backup-related operational status information (information regarding the primary tier storage device, secondary tier storage device, and backup data) based on the information received from the third storage device 230 in the primary tier.

[0193] Step 1975 : The first storage device 210 creates execution information for the backup-related recovery process, and stores it in the recovery task table 7100 .

[0194] Step 1995: The backup system temporarily ends this processing flow.

[0195] 20A and 20B are flowcharts showing the device switching flow of the secondary layer. The backup system starts processing from step 2000 and proceeds to step 2005.

[0196] Step 2005: The second storage device 220 acquires information about connectable secondary tier storage devices.

[0197] Step 2010: The second storage device 220 calculates the operation score of the switchable storage device. The second storage device 220 calculates the operation score based on the evaluation score table 1200, using the following formula: operation score fop(s) = (predicted capacity consumption score) × w1 (priority weight) + (actual operation cost) × w2 (priority weight). In the formula, the predicted capacity consumption score is calculated using the following formula: predicted capacity consumption score = {(full backup capacity + differential backup capacity)} × capacity reduction rate (%), the total operation cost is calculated using the following formula: total operation cost (yen / month) = estimated capacity cost + estimated I / O cost, and the actual operation cost is calculated using the following formula: actual operation cost (yen / month) = actual capacity cost + actual I / O cost.

[0198] Step 2015: The second storage device 220 determines the storage device with the smallest value among the calculated operation scores including the operation score of the storage device currently in operation as the switching destination.

[0199] Step 2020: The second storage device 220 determines whether the connection between the switching destination storage device and the primary tier storage device is normal. If the connection between the switching destination storage device and the primary tier storage device is not normal, the second storage device 220 determines "NO" and proceeds to step 2025. If the connection between the switching destination storage device and the primary tier storage device is normal, the second storage device 220 determines "YES" and proceeds to step 2030 in Figure 20B.

[0200] Step 2025: The second storage device 220 calculates the operational scores from the remaining switchable storage devices other than the switching destination storage device determined in step 2015, and proceeds to step 2015 again to determine the storage device (in this example, the fifth storage device 250) having the smallest operational score calculated from the remaining switchable storage devices as the switching destination. Thereafter, the storage device proceeds to step 2020 and executes the processing of step 2020 described above.

[0201] Step 2030: The fifth storage device 250 sends a command to restore the backup data to the storage device in the primary tier (the second storage device 220 in this example).

[0202] Step 2035: The second storage device 220 copies the backup data of the primary tier to the storage device of the secondary tier (the fifth storage device 250 in this example).

[0203] Step 2040: The fifth storage device 250 updates the operation status of the secondary tier storage device in the backup relationship.

[0204] Step 2045: The fifth storage device 250 sends information about the backup data of the fifth storage device 250 belonging to the secondary tier of the backup relationship (information about the primary tier storage device, the secondary tier storage device and the backup data) to the first storage device 210 where the original data A is stored.

[0205] Step 2050: The first storage device 210 updates all backup-related operational status information (information regarding the primary tier storage device, secondary tier storage device and backup data) based on the information received from the fifth storage device 250 in the secondary tier.

[0206] Step 2055 : The first storage device 210 creates execution information for the backup-related recovery process, and stores it in the recovery task table 7100 .

[0207] Step 2095: The backup system temporarily ends this processing flow.

[0208] <Effects> As described above, the backup system according to the fourth embodiment of the present invention achieves the same effects as those of the first embodiment. Furthermore, the backup system according to the fourth embodiment of the present invention can perform backup operations efficiently by optimizing the storage devices (primary tier storage devices and secondary tier storage devices) that constitute a backup relationship based on the operation score.

[0209] <<Modifications>> The present invention is not limited to the above-described embodiments, and various modifications can be adopted within the scope of the present invention. Furthermore, the above-described embodiments can be combined with each other without departing from the scope of the present invention. [Explanation of symbols]

[0210] 100a to 100c...host, 210...first storage device, 220...second storage device, 230...third storage device, 240...fourth storage device, 250...fifth storage device, 3000...monitoring task table, 4000...condition table, 5000...backup table, 6000...BK location table, 7000...storage layer table, 7100...recovery task table

Claims

1. A backup system including a plurality of backup storage devices for storing backup data of data to be backed up stored in a storage device, the plurality of backup storage devices are classified as the backup storage devices belonging to either a primary tier or a secondary tier; the storage device stores primary backup data, which is backup data of the data to be backed up, in the backup storage device belonging to the primary tier, and the backup storage device belonging to the primary tier stores secondary backup data, which is backup data of the primary backup data, in the backup storage device belonging to the secondary tier, thereby backing up the data to be backed up; Backup system.

2. 2. The backup system according to claim 1, The storage device determine whether the connection status between the storage device and a primary tier backup storage device, which is the backup storage device belonging to the primary tier in which the primary backup data is stored, is normal; and determine whether the connection status between the primary tier backup storage device and a secondary tier backup storage device, which is the backup storage device belonging to the secondary tier in which the secondary backup data is stored, is normal; Backup system.

3. 3. The backup system according to claim 2, The storage device If the connection status between the storage device and the primary tier backup storage device is not normal, switching the storage destination of the primary backup data to another backup storage device belonging to the primary tier, the secondary tier backup storage device sends a copy of the secondary backup data to another backup storage device belonging to the primary tier as a switching destination; The other backup storage device belonging to the primary tier as the switching destination restores the primary backup data from a copy of the secondary backup data, the primary layer backup storage device, If the connection status between the primary tier backup storage device and the secondary tier backup storage device is not normal, switching the storage destination of the secondary backup data to another backup storage device belonging to the secondary tier, Sending a copy of the primary backup data to another backup storage device belonging to the secondary tier of the switching destination; The other backup storage device belonging to the secondary tier as the switching destination restores the secondary backup data from a copy of the primary backup data. Backup system.

4. 4. The backup system according to claim 3, The storage device If the connection state between the storage device and the primary tier backup storage device is not normal, determining whether there is another backup storage device that belongs to the primary tier and can be switched; If there is another backup storage device belonging to the primary tier that can be switched, switching the storage destination of the primary backup data to the other backup storage device belonging to the primary tier, If there is no other backup storage device belonging to the primary tier that can be switched, an alert is issued regarding an abnormal state of the backup relationship. Backup system.

5. 4. The backup system according to claim 3, the primary layer backup storage device, If the connection state between the primary tier backup storage device and the secondary tier backup storage device is not normal, determine whether there is another backup storage device belonging to the secondary tier that can be switched; If there is another backup storage device that belongs to the secondary tier and that can be switched, switching the storage destination of the secondary backup data to the other backup storage device that belongs to the secondary tier, If there is no other backup storage device that belongs to the secondary tier and can be switched, an alert is issued regarding an abnormal state of the backup relationship. Backup system.

6. 4. The backup system according to claim 3, The storage device If the connection state between the storage device and the primary tier backup storage device is not normal, determining whether there is another backup storage device that belongs to the primary tier and can be switched; If there are a plurality of other backup storage devices belonging to the switchable primary tier, an operation score is calculated to evaluate the operation status of the plurality of other backup storage devices, and based on the operation score, the other backup storage device to be switched to is selected from the plurality of other backup storage devices; Switching the storage destination of the primary backup data to another backup storage device belonging to the selected primary tier. Backup system.

7. 4. The backup system according to claim 3, the primary layer backup storage device, If the connection state between the primary tier backup storage device and the secondary tier backup storage device is not normal, determine whether there is another backup storage device belonging to the secondary tier that can be switched; If there are a plurality of other backup storage devices belonging to the secondary tier that can be switched, an operation score is calculated to evaluate the operation status of the plurality of other backup storage devices, and based on the operation score, the other backup storage device to be switched to is selected from the plurality of other backup storage devices; Switching the storage destination of the secondary backup data to another of the backup storage devices belonging to the selected secondary tier; Backup system.

8. 4. The backup system according to claim 3, The storage device After switching the storage destination of the primary backup data to another backup storage device belonging to the primary tier, determine whether or not the connection status between the storage device and the backup storage device belonging to the primary tier before the switching is normal; When the connection status between the storage device and the backup storage device belonging to the primary tier before the switchover is normal, the storage destination of the primary backup data is switched from the other backup storage device belonging to the primary tier to the backup storage device belonging to the primary tier before the switchover. Backup system.

9. 4. The backup system according to claim 3, The storage device After switching the storage destination of the secondary backup data to another backup storage device belonging to the secondary tier, determine whether or not the connection status between the primary tier backup storage device and the backup storage device belonging to the secondary tier before the switch is normal; the primary layer backup storage device, When the connection status between the primary tier backup storage device and the backup storage device belonging to the secondary tier before the switch is normal, the storage destination of the secondary backup data is switched from the other backup storage device belonging to the secondary tier to the backup storage device belonging to the secondary tier before the switch. Backup system.

10. 9. The backup system according to claim 8, The storage device When the connection state between the storage device and the backup storage device belonging to the primary tier before the switchover is normal, calculate an operation score for calculating the operation state of the backup storage device belonging to the primary tier before the switchover and another backup storage device belonging to the primary tier after the switchover; If the operational score of the backup storage device belonging to the primary tier before the switch is better than the operational score of another backup storage device belonging to the primary tier, switch the storage destination of the primary backup data from the other backup storage device belonging to the primary tier to the backup storage device belonging to the primary tier before the switch. Backup system.

11. 10. The backup system according to claim 9, the primary layer backup storage device, When the connection status between the primary tier backup storage device and the backup storage device belonging to the secondary tier before the switchover is normal, calculate an operation score for calculating the operation status of the backup storage device belonging to the secondary tier before the switchover and the other backup storage devices belonging to the secondary tier after the switchover; If the operational score of the backup storage device belonging to the secondary tier before the switch is better than the operational score of the other backup storage devices belonging to the secondary tier, switch the storage destination of the secondary backup data from the other backup storage devices belonging to the secondary tier to the backup storage device belonging to the secondary tier before the switch. Backup system.

12. 2. The backup system according to claim 1, the storage device calculates an operational score for calculating the operational status of the other backup storage devices belonging to the primary tier; determining whether to switch the storage destination of the primary backup data to another backup storage device belonging to the primary tier based on the operation score, and switching the storage destination of the primary backup data to another backup storage device belonging to the primary tier based on a result of the determination; The backup storage device belonging to the secondary tier in which the secondary backup data is stored sends a copy of the secondary backup data to another backup storage device belonging to the primary tier as a switching destination, The other backup storage device belonging to the primary tier as the switching destination restores the primary backup data from a copy of the secondary backup data, The backup storage device belonging to the primary tier in which the primary backup data is stored calculates an operation score for calculating the operation status of the other backup storage devices belonging to the secondary tier, determining whether to switch the storage destination of the secondary backup data to another backup storage device belonging to the secondary tier based on the operation score, and switching the storage destination of the secondary backup data to another backup storage device belonging to the secondary tier based on a result of the determination; The backup storage device belonging to the primary tier in which the primary backup data is stored sends a copy of the primary backup data to another backup storage device belonging to the secondary tier as a switching destination; The other backup storage device belonging to the secondary tier as the switching destination restores the secondary backup data from a copy of the primary backup data. Backup system.

13. A backup method using a plurality of backup storage devices for storing backup data of data to be backed up stored in a storage device, comprising: the plurality of backup storage devices are classified as the backup storage devices belonging to either a primary tier or a secondary tier; the storage device stores primary backup data, which is backup data of the data to be backed up, in the backup storage device belonging to the primary tier, and the backup storage device belonging to the primary tier stores secondary backup data, which is backup data of the primary backup data, in the backup storage device belonging to the secondary tier, thereby backing up the data to be backed up; Backup method.

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