Device for managing storage system

Abstract

To provide a device for managing a storage system that guarantees performance after failover.SOLUTION: A device stores storage resource management information that manages information on a throughput performance resource and a response time of storage devices at a main site and a remote site. The device receives performance requirements, including response performance and throughput performance, for a volume copy pair consisting of a primary volume at the main site and a secondary volume at the remote site. The device refers to the storage resource management information and determines whether there is a storage device that satisfies the performance requirements at both the main site and the remote site. The device determines, when there is a storage device that satisfies the performance requirements at both the main site and the remote site, to create the volume copy pair.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the management of storage systems. [Background technology]

[0002] In recent years, the use of cloud computing in IT infrastructure has increased, and on-premise environments are also beginning to adopt cloud-like approaches. Cloud-like operations have shifted from the traditional approach of infrastructure managers designing infrastructure to match application requirements to a self-service approach where application engineers select and use infrastructure that meets their requirements from among the infrastructure designed by the infrastructure manager, based on predefined service levels. In these operations, it is important to ensure that the defined service levels are actually met, and the same is true for copy pair configurations for disaster recovery.

[0003] Storage systems that store data redundantly between remote locations are known to protect important data from datacenter-level failures caused by disasters and other factors. For example, a function called storage remote copy is known, which copies data between paired volumes and maintains data consistency when a host computer issues a data write request. Known examples of this type of remote copy include synchronous copy and asynchronous copy.

[0004] In disaster recovery, the configurations of storage devices performing remote copying may be aligned to prevent performance degradation after failover. For example, Japanese Patent Application Laid-Open Publication No. 2007-328468 discloses pairing a primary volume and a secondary volume in the same storage tier. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-328468 Summary of the Invention [Problem to be solved by the invention]

[0006] For example, in a configuration in which remote copying is performed within a self-service infrastructure in which an application engineer can operate the infrastructure, the application engineer requests that a predetermined performance requirement be met after a failover. [Means for solving the problem]

[0007] One aspect of the present invention is an apparatus for managing a storage system, comprising a processor and a storage device, wherein the storage device stores storage resource management information that manages information on throughput performance resources and response times of storage devices at a main site and a remote site, and the processor receives performance requirements, including response performance and throughput performance, for a volume copy pair consisting of a primary volume at the main site and a secondary volume at the remote site, and refers to the storage resource management information to determine whether there are storage devices at both the main site and the remote site that satisfy the performance requirements, and if there are storage devices at both the main site and the remote site that satisfy the performance requirements, determines to create the volume copy pair. [Effects of the Invention]

[0008] In a copy pair, the performance of the volume can be maintained after a failover. [Brief explanation of the drawings]

[0009] [Figure 1] 1 illustrates a logical configuration of a system according to an embodiment of the present specification. [Figure 2] FIG. 2 illustrates an example of a hardware configuration of a storage operation management server according to an embodiment of the present specification. [Figure 3]An example of the configuration of a service catalog database is shown below. [Figure 4] 10 shows an example of the configuration of a volume information database. [Figure 5] 1 shows an example of the configuration of a storage resource management database. [Figure 6] 10 shows an example of the configuration of a site warning threshold management database. [Figure 7] The service catalog interface unit prompts the user for input via the GUI of the terminal, and shows an example of information received from the user. [Figure 8] The volume performance requirements generated from the volume-related information for the volume named "Prod1" are shown. [Figure 9A] 10 is a flowchart of an example of a process for creating one volume or one remote copy pair by a volume creation unit. [Figure 9B] 10 is a flowchart of an example of a process for creating one volume or one remote copy pair by a volume creation unit. [Figure 10] The performance requirements for volume Test2 calculated by the service catalog interface unit are shown below. [Figure 11] 1 shows an update of the storage resource management database. [Figure 12] The figure shows a state in which information about a new volume Test2 has been added to a volume information database in which information about an existing volume Test1 has been registered. [Figure 13] 10 shows a flowchart of an example of processing by a storage management support unit. [Figure 14] 10 shows an example of an alert image displayed on the IT administrator's terminal by the storage management support unit. [Figure 15A] 10 shows a flowchart of an example of processing by a volume creation unit in the second embodiment. [Figure 15B] 10 shows a flowchart of an example of processing by a volume creation unit in the second embodiment. [Figure 16] 10 shows a flowchart of an example of processing by a storage management support unit during failover in the second embodiment. [Figure 17] 13 shows a flowchart of an example of processing by a storage management support unit in the third embodiment. [Figure 18] 13 shows a flowchart of a process for determining whether to perform rebalancing when the minimum performance resource amount exceeds a threshold in the third embodiment. [Figure 19] 10 shows a flowchart of a rebalancing decision when the maximum performance resource amount exceeds the performance resource amount of the storage device in the third embodiment. [Figure 20] 13 shows an example of an alert image presented on the terminal of an IT manager by the storage management support unit in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] In the following, when necessary for convenience, the description will be divided into multiple sections or examples, but unless otherwise specified, they are not unrelated to each other, and one is related to the other as a partial or complete modification, detail, supplementary explanation, etc. Furthermore, in the following, when the number of elements, etc. (including the number, numerical value, amount, range, etc.) is mentioned, it is not limited to that specific number, and may be more or less than the specific number, unless otherwise specified or when it is clearly limited in principle to a specific number, etc.

[0011] A computer system can be composed of one computer or multiple computers that can communicate with each other. A computer device, computer system, or group of computing resources includes one or more interface devices (including, for example, communication devices and input / output devices), one or more storage devices (including, for example, memory (main memory) and auxiliary storage devices), and one or more processors.

[0012] When a function is realized by executing a program by a processor, the defined processing is performed using a storage device and / or an interface device, etc., so the function may be considered to be at least a part of the processor. Processing described using a function as the subject may also be processing performed by a processor or a system having that processor.

[0013] The program may be installed from a program source. The program source may be, for example, a program distribution computer or a computer-readable storage medium (e.g., a computer-readable non-transitory storage medium). The description of each function is an example, and multiple functions may be combined into one function or one function may be divided into multiple functions.

[0014] In the following description, information that provides an output in response to an input may be described using expressions such as "xxx table," but this information may be data of any structure. Therefore, an "xxx table" may be referred to as "xxx information." Furthermore, in the following description, the structure of each table is an example, and one table may be divided into two or more tables, or two or more tables may all or partly be one table.

[0015] In the embodiments of this specification, the throughput performance that a storage device can provide to a volume is called a performance resource. The performance resource amount of a storage device is the upper limit of the throughput performance that the storage device can provide. Furthermore, the performance resource that has been allocated to each volume is called a consumed performance resource. The total sum of the consumed performance resources within a storage device is called the consumed performance resource amount.

[0016] The amount of throughput performance that a storage device can provide to a volume is determined by the processing performance of the processor that the storage device has, the memory bandwidth, the throughput of the storage drive, etc. These performance characteristics of the storage device are measured in advance, and the performance resource amount of the storage device is set in advance based on the measurement results. [Example]

[0017] An embodiment of this specification will be described below. This embodiment describes a method for configuring a remote copy pair that can guarantee performance at the copy destination after a failover (FO). A remote copy pair is a pair consisting of a main volume (primary volume) at the copy source and a remote volume (secondary volume) at the copy destination.

[0018] FIG. 1 illustrates a logical configuration of a system according to an embodiment of the present specification. The system includes a site A 10A and a site B 10B that is remote from the site A 10A. Each of the sites 10A and 10B includes one or more storage devices and one or more host servers that access the storage devices. In the exemplary configuration of FIG. 1, the site A 10A is an on-premise site, and the site B 10B is a cloud site. Note that the site B 10B may also be an on-premise site. The sites A 10A and B 10B can communicate via a WAN.

[0019] 1, site A 10A is provided with storage device a 100A, storage device b 100B, and also has host server 150A. Site B 10B is provided with storage device c 100C, storage device d 100D, and also has host server 150B.

[0020] Each storage device includes a volume 101 for storing data, a remote copy unit 111, and a QoS (Quality of Service) unit 112. In FIG. 1, the components of storage device a 100A are assigned reference numerals as an example. The remote copy unit 111 executes and manages remote copying. For disaster recovery (DR), volumes formed at site A 10A and site B 10B form a remote copy pair. One site is the main site or primary site, and the other site is the remote site or secondary site. Data updates to the primary volume are reflected synchronously or asynchronously in the secondary volume.

[0021] The QoS (Quality of Service) unit controls I / O processing on a volume-by-volume basis so that the performance set for each volume is provided. Specifically, the QoS unit controls I / O processing on a volume-by-volume basis so that the upper and lower performance limits (performance limit values) set for each volume are met.

[0022] Host servers 150A and 150B access storage devices at the same site by executing application program 151. In Fig. 1, the components of host server 150A are given reference numerals as an example.

[0023] The storage operation management server 200 exists, for example, on a cloud and manages the storage devices of the site A 100 A and the site B 100 B. An application engineer and an IT administrator (also called an infrastructure administrator) can access the storage operation management server 200 and the systems in the site A 100 A and the site B 100 B using terminals 301 and 302, respectively.

[0024] The storage operation management server 200 creates and manages volumes and remote copy pairs in response to access from terminals 301 and 302. The storage operation management server 200 includes functional units of a service catalog interface unit 201, a volume creation unit 202, and a storage management support unit 203. The storage operation management server 200 further stores management information, and this management information includes a service catalog database 210, a volume information database 230, a storage resource management database 240, and a site warning threshold management database 250.

[0025] 2 is a diagram illustrating an example of the hardware configuration of the storage operation management server 200 according to an embodiment of the present specification. An example of the hardware configuration of the storage operation management server 200 will be described below, but the user terminals 301 and 302 and the host servers 150A and 150B may also have a similar configuration.

[0026] Each of the storage devices 100A-100D may include one or more storage controllers and multiple storage drives. The storage drives may be shared by multiple storage devices. In addition to a processor and memory, the storage controller may include a front-end interface with the host and a back-end interface with the storage drives. The processor and / or logic circuitry of the storage controller may implement each of the functional units of the storage device.

[0027] The storage operation management server 200 includes a CPU (processor) 281 that executes various programs, a memory (main storage device) 282 that stores the various programs, and an auxiliary storage device 283 that stores various data. The CPU 281 can include one or more cores, and the memory 282 is, for example, a DRAM that includes a volatile storage area. The auxiliary storage device 283 is, for example, an HDD (hard disk drive) or flash memory, and can provide a non-volatile storage area.

[0028] The storage operation management server 200 further includes an output device 284 for presenting information to the user of the device, an input device 285 for inputting instructions, images, etc. from the user, and a communication device 286 for communicating with other devices. These are connected to each other by a bus 287.

[0029] The functional units of the storage operation management server 200 shown in Fig. 1 can be implemented by, for example, the CPU 281 operating in accordance with a program. The CPU 281 reads and executes various programs from the memory 282 as necessary. The memory 282 can store programs corresponding to the functional units 201, 202, and 203 shown in Fig. 1. Each program is loaded into the memory 282 from the auxiliary storage device 283, for example, and executed by the CPU 281. At least a portion of the functional units may be configured with logic circuits.

[0030] The auxiliary storage device 283 stores data that is referenced or managed by various programs. For example, the auxiliary storage device 283 can store the databases 210, 230, 240, and 250 shown in FIG.

[0031] The output device 284 is composed of devices such as a display, printer, and speaker. The input device 285 is composed of devices such as a keyboard, mouse, and microphone. The output device 284 presents the results of input from the user and also presents the results of processing by the storage operation management server 200. Instructions from the user are input to the storage operation management server 200 by the input device 285. When a user terminal 3 is used, its input / output devices function in the same way, and the output device 284 and input device 285 can be omitted.

[0032] The communication device 286 is connected to a system including the user terminals 301, 302 and the storage devices in the sites 10A, 10B via a network (for example, the Internet), receives data sent from other devices, and sends the results of processing by the storage operation management server 200 to other devices. Note that some devices may be omitted.

[0033] Various types of information stored in the storage operation management server 200 will be explained below. Fig. 3 shows an example of the configuration of the service catalog database 210. The service catalog database 210 manages the service levels (service catalog) that the system provides to volumes. The service levels indicate information on guaranteed performance and costs for volumes. The service catalog database 210 may be prepared in advance by a service provider.

[0034] In the example configuration shown in Figure 3, the service catalog database 210 has a Catalog Name column 211, a Unit Cost column 212, a DR Cost column 213, a Unit Capacity column 214, a Unit Max Write Throughput column 215, a Unit min Write Throughput column 216, a Unit Max Read Throughput column 217, a Unit min Read Throughput column 218, and a P99 Response Time column 219.

[0035] The Catalog Name column 211 indicates the name that identifies the service level (service catalog). The Unit Cost column 212 indicates the cost per unit of each service level. One or more units can be assigned to each volume or remote copy volume pair. The DR Cost column 213 indicates the cost when a remote copy pair is configured for disaster recovery.

[0036] The Unit Capacity column 214 indicates the capacity allocated to the volume per unit. The Unit Max Write Throughput column 215 indicates the maximum write throughput per unit. When multiple units are allocated, the product of the value indicated in the Unit Max Write Throughput column 215 and the number of units becomes the maximum write throughput of the volume.

[0037] The Unit min Write Throughput column 216 indicates the minimum value of write throughput per unit. When multiple units are allocated, the product of the value indicated in the Unit min Write Throughput column 216 and the number of units becomes the minimum value of write throughput for the volume. The write throughput of the volume is controlled so that it falls within the range between the maximum and minimum values.

[0038] The Unit Max Read Throughput column 217 indicates the maximum value of read throughput per unit. When multiple units are allocated, the product of the value indicated in the Unit Max Read Throughput column 217 and the number of units becomes the maximum value of read throughput for the volume.

[0039] The Unit min Read Throughput column 218 indicates the minimum read throughput per unit. When multiple units are allocated, the product of the value indicated in the Unit min Read Throughput column 218 and the number of units becomes the minimum read throughput for the volume. The read throughput of the volume is controlled so that it falls within the range between the maximum and minimum values.

[0040] The P99 Response Time column 219 indicates the upper limit of the response time for 99% of the volume's predefined IOs. The predefined IO may be, for example, a read request for a specified amount of data. For example, the response time for 99% of 4KB read requests is guaranteed to be less than the value indicated in column 219.

[0041] 4 shows an example of the configuration of the volume information database 230. The volume information database 230 manages information on volumes at the main site. The volume information database 230 is updated and managed by the storage operation management server 200.

[0042] In the configuration example shown in FIG. 4, the volume information database 230 has a Volume Name column 231 , a Catalog Name column 232 , a Number of Units column 233 , a DR column 234 , a Site column 235 , a Storage Apparatus column 236 , and an Actual Storage Apparatus column 237 .

[0043] The Volume Name column 231 indicates a name that identifies the volume. The Catalog Name column 232 indicates a service catalog name (service level name) that is assigned to the volume. The Number of Units column 233 indicates the number of service units that are assigned to the volume.

[0044] The DR column 234 indicates whether a disaster recovery function is being used. In other words, it indicates whether a secondary volume (remote volume) exists at a secondary site (remote site) that forms a remote copy pair with the main volume. The Site column 235 indicates the site where each single volume or remote copy pair volume exists. The Storage Apparatus column 236 indicates the managed storage device that stores each single volume or remote copy pair volume. The Actual Storage Apparatus column 237 indicates the actual storage device that stores each single volume or remote copy pair volume.

[0045] 5 shows an example of the configuration of the storage resource management database 240. The storage resource management database 240 manages the performance resources of each storage device in the system. As described above, the performance resource amount of a storage device is expressed in this example as throughput (MB / s).

[0046] In the configuration example shown in FIG. 5, the storage resource management database 240 has a Storage Apparatus column 241 , a Capacity column 242 , a Response time column 243 , a Performance Resource Consumption column 244 , a Max Performance Resource column 245 , a Site column 246 , and an Actual capacity Usage column 247 .

[0047] The Storage Apparatus column 241 indicates an identifier for identifying a storage device. The Capacity column 242 indicates the capacity of the storage area of ​​the storage device. The Response Time column 243 indicates the response time of the storage device. Here, it indicates the upper limit of the response time for 99% of predefined IOs. The predefined IO may be, for example, a read request for a specified amount of data.

[0048] The Performance Resource Consumption column 244 indicates the amount of consumed performance resources (throughput performance) of the storage device. The Max Performance Resource column 245 indicates the total performance resources of the storage device. The Site column 246 indicates the site where the storage device is located. The Actual Capacity Usage column 247 indicates the amount of storage space used in the storage device.

[0049] In the storage resource management database 240, the Performance Resource Consumption column 244 and the Actual capacity Usage column 247 are updated by the storage operation management server 200. Information in the other columns is set in advance by, for example, the service provider.

[0050] Fig. 6 shows an example of the configuration of the site alert threshold management database 250. The site alert threshold management database 250 manages thresholds that are referenced to determine whether to issue an alert for each site. In the example configuration of Fig. 5, the site alert threshold management database 250 has a Site column 251 and an Alert Threshold column 252. The Site column 251 indicates the site identifier, and the Alert Threshold column 252 indicates the alert threshold for each site. Details of how to use the alert thresholds will be described later.

[0051] Next, we will explain the information that an application engineer, who is a user of the service, enters to create a volume only at the main site or to create a remote copy volume pair at the main site and a remote site. Figure 7 shows an example of the information that the service catalog interface unit 201 prompts the user to enter via the GUI of the terminal 301 and receives from the user.

[0052] In the configuration example shown in FIG. 7, the user input 270 has a table configuration that allows information on multiple volumes to be entered simultaneously, and has a Volume Name column 271, a Catalog Name column 272, a Number of Units column 273, a DR column 274, a Main Site column 275, and a Remote Site column 276.

[0053] The Volume Name field 271 is a field for inputting the volume name. The Catalog Name field 272 is a field for inputting the service catalog (service level) name for the volume. The Number of Units field 273 is a field for inputting the number of units of the specified service catalog.

[0054] The DR column 274 is a column for entering information on whether disaster recovery is required. In other words, it is a column for entering whether or not there is a remote volume that constitutes a copy pair. The Main Site column 275 and Remote Site column 276 are columns for entering the main site and remote site, respectively. For volumes that do not constitute a copy pair, only the main site is entered.

[0055] After the corresponding volume is created, the input information is stored in the volume information database 230. Specifically, the information is stored in a Volume Name column 231, a Catalog Name column 232, a Number of Units column 233, a DR column 234, and a Site column 235.

[0056] The following describes the process of creating a volume in accordance with a volume creation request from a user. The service catalog interface unit 201 determines the performance requirements of the volume from the volume-related information input by the user, as described with reference to Fig. 7. The volume creation unit 202 creates a volume so as to satisfy the performance requirements.

[0057] First, a method for calculating volume performance requirements from volume-related information entered by the user will be explained. Fig. 8 shows volume performance requirements 310 generated from volume-related information for volume name "Prod1". The volume performance requirements 310 have a Volume Name column 311, a DR column 312, a Main Site column 313, a Remote Site column 314, a Cost column 315, a Capacity column 316, a Max Write Throughput column 317, a Min Write Throughput column 318, a Max Read Throughput column 319, a Min Read Throughput column 320, and a P99 Response Time column 321.

[0058] The user input information is the record of "Prod1" in the user input 270 shown in Fig. 7. The service catalog interface unit 201 stores the values ​​of the Volume Name column 271, the DR column 274, the Main Site column 275, and the Remote Site column 276 in the Volume Name column 311, the DR column 312, the Main Site column 313, and the Remote Site column 314 of the volume performance requirement 310, respectively.

[0059] Furthermore, the service catalog interface unit 201 searches for "Silver" in the Catalog Name column 211 of the service catalog database 210 shown in FIG. 2 based on "Silver" entered in the Catalog Name column 272 of the entry for "Prod1," and reads out that entry.

[0060] 3, in the entry for the service catalog "Silver," the value in the Unit Capacity column 214 is 100, the value in the Unit Max Write Throughput column 215 is 50, the value in the Unit min Write Throughput column 216 is 40, the value in the Unit Max Read Throughput column 217 is 100, and the value in the Unit min Read Throughput column 218 is 80.

[0061] The service catalog interface unit 201 obtains the value of the Number of Units column 273 from the entry of the user input 270 for "Prod1." In this example, the number of units is 15. The service catalog interface unit 201 calculates the product of the number of units, 15, and each of the above values ​​in the service catalog "Silver," and calculates and stores the values ​​of columns 316 to 320 indicating volume performance in the volume performance requirement 310. The value of the P99 Response Time column 219 in the service catalog database 210 is stored in the P99 Response Time column 321.

[0062] Next, a method for calculating service costs will be explained. In the entry for service catalog "Silver," the value in the Unit Cost column 212 is 0.3, and the value in the DR Cost column 213 is 5 times that. Furthermore, the DR column 274 for "Prod1" in the user input 270 indicates "Yes." Therefore, the value in the Cost column 315 in the volume performance requirement 310 is calculated by multiplying these by 15, the number of units.

[0063] The volume creation unit 202 creates a volume that satisfies the volume performance requirement 310 within the system, and if it is not possible to create a volume that satisfies the volume performance requirement 310, it notifies the user of an error.

[0064] The following describes in detail the processing of the volume creation unit 202. Figures 9A and 9B are flowcharts of an example of processing by the volume creation unit 202 to create one volume or one remote copy pair.

[0065] First, the volume creation unit 202 receives (S11) a volume creation request from the service catalog interface unit 201. The volume creation request is accompanied by a volume performance requirement as described with reference to FIG.

[0066] The volume creation unit 202 determines whether it is possible to create a volume that satisfies the performance requirements within the main site. In other words, the volume creation unit 202 determines whether there is a storage device at the main site that has remaining performance resources that satisfy the volume performance requirements (S12).

[0067] If a volume that satisfies the specified performance requirements cannot be created at the main site (S12: NO), the volume creation unit 202 notifies the terminal 301 of an error (S13), which ends this flow.

[0068] If a volume that satisfies the specified performance requirements can be created at the main site (S12: YES), the volume creation unit 202 references the DR column 312 of the volume performance requirements 310 and determines whether DR is necessary (S14).

[0069] If DR is not required (S14: NO), the volume creation unit 202 registers information about the volume to be created in the volume information DB 230 (S15). Furthermore, the volume creation unit 202 updates the performance resource consumption amount in the Performance Resource Consumption column 244 of the storage resource management DB 240 (S16).

[0070] If there is a change in the suppression level ρ of performance resource allocation set for an existing volume in the storage device, the volume creation unit 202 updates that value (S17). The suppression level of performance resource allocation will be described later. Next, the volume creation unit 202 creates a volume at the main site (S18), and further sets the performance requirements (QoS) of the created volume in the QoS unit 112 (S19). The QoS unit 112 executes IO control etc. in accordance with the upper and lower limits of throughput set for each volume, and controls the allocation of performance resources from the storage device to the volume.

[0071] If it is determined in step S14 that DR is necessary (S14: YES), the flow proceeds to step S20 in FIG. 9B via connector A. The volume creation unit 202 determines whether it is possible to create a volume that satisfies the performance requirements in the remote site (S20). If it is not possible to create a volume that satisfies the specified performance requirements in the remote site (S20: NO), the volume creation unit 202 notifies the terminal 301 of an error (S21). This ends the flow.

[0072] If volumes that satisfy the specified performance requirements can be created at the remote site (S20: YES), the volume creation unit 202 registers information about the two volumes to be created in the volume information DB 230 (S22). Furthermore, the volume creation unit 202 updates the performance resource consumption amounts of the storage devices at the main site and the remote site in the Performance Resource Consumption column 244 of the storage resource management DB 240 (S23).

[0073] If there is a change in the suppression rate ρ of performance resource allocation set for an existing volume in the storage device at each of the main site and the remote site, the volume creation unit 202 updates that value (S24). Next, the volume creation unit 202 creates volumes at the main site and the remote site (S18), and further sets the performance requirements (QoS) of the created volumes in the QoS units 112 of the storage devices at the two sites (S19). The QoS unit 112 executes IO control and the like in accordance with the upper and lower limits of throughput set for each volume, and controls the allocation of performance resources from the storage devices to the volumes.

[0074] The following describes in detail the processes S12 and S20 in which the volume creation unit 202 determines whether a volume can be created at the main site or the remote site.

[0075] First, the following variables are defined: Pij: The maximum amount of resources consumed when volume i belongs to storage device j Ri: The product of the Max read throughput and the number of units in the selected catalog ri: The product of the Min read throughput and the number of units in the selected catalog Wi: Max write throughput in the selected catalog and the number of units wi: The product of the Min write throughput and the number of units in the selected catalog

[0076] αj: Coefficient that determines the performance resource consumption of read throughput in storage device j βj: Coefficient that determines the performance resource consumption of write throughput in storage device j Uj: Amount of performance resources consumed by storage device j Tj: performance resource amount of storage device j δij: Whether volume i belongs to storage device j (true: 1, false: 0) σij: Does storage device j satisfy the response requirements for volume i? (True: 1, False: 0) ρij: Coefficient (suppression degree) that determines how much the performance of volume i in storage device j is suppressed

[0077] Furthermore, the volume creation unit 202 can use the following formula to manage performance resources: Pij=max(αjRi,βjWi) pij=max(αjri,βjwi) Uj=Σ i=1 n δij×ρij×Pij

[0078] The volume creation unit 202 searches for and finds a value ρ that satisfies the following formula, and if so, determines that a volume can be created. ρi+1,j×Pi+1,j <max(σij(Ti-Uj)) Pij≧ρij×Pij≧pij 0≦ρij≦1

[0079] When the volume creation unit 202 finds ρP that satisfies the performance conditions, it updates ρ of each volume of the storage device j in which that volume is to be created, and creates a new volume (at this time, calculation is performed so that Uj=Tj).

[0080] The combination of ρ can be determined by a combinatorial optimization process. The volume creation unit 202 may search for a combination of ρ using, for example, artificial intelligence (machine learning model). There are several known methods for searching for a combination of ρ. For example, it is possible to make the ρ as large as possible uniformly within the storage device, to extremely suppress a portion so that the range of influence within the storage device is as small as possible, or to assign priorities to each policy grade within the storage device.

[0081] By using the above method, the volume creation unit 202 can select the storage device that can satisfy the volume performance requirements and has the largest remaining resource consumption.

[0082] As described above, a maximum throughput requirement and a minimum throughput requirement are assigned to each volume, and the volume creation unit 202 creates a volume when the amount of performance resources that the storage device can provide and the amount of required performance resources are met. The amount of performance resources required is greater under the maximum throughput requirement than under the minimum throughput requirement. Therefore, even if the maximum throughput requirement cannot be met, if the minimum throughput requirement can be met, the volume creation unit 202 creates a new volume by suppressing the performance of each volume in the storage device. If the minimum throughput requirement of the new volume cannot be met, the volume creation unit 202 notifies an error without creating the new volume.

[0083] The following describes an example of processing by the volume creation unit 202. Here, it is assumed that only volume Test1 has been created and a request to create volume Test2 has been received.

[0084] 10 shows the performance requirements 310 for volume Test2 calculated by the service catalog interface unit 201. The volume creation unit 202 searches for a storage device in site A 10A, the main site, that can meet the response time requirement "10". The volume creation unit 202 finds that storage device a 100A and storage device b 100B meet the requirement.

[0085] The volume creation unit 202 calculates the remaining performance resources from the performance resource amounts and consumed performance resource amounts of the storage device a 100A and storage device b 100B. Since Test1 has been created in the storage device a 100A and the consumed performance resource amount is 1800, it is calculated that the remaining performance resources in the storage device a 100A are 6000-1800=4200 and in the storage device b 100B are 5000.

[0086] The volume creation unit 202 calculates the performance resources required to satisfy the throughput performance of volume Test2 using coefficients α and β specific to the storage device a 100A and storage device b 100B that can be allocated. α and β are set in advance based on the results of advance measurements, etc. Here, α=0.6 and β=0.5 for storage device a 100A, and α=0.5 and β=0.4 for storage device b 100B.

[0087] From the maximum read throughput requirement of "2000" and the maximum write throughput requirement of "1000" for volume Test2, it is determined that αR=1200>βW=500 for storage device a 100A, and αR=1000>βW=400 for storage device b 100B. Therefore, it is found that the amount of performance resources required to create volume Test2 in storage device a 100A is 1200, and the amount of performance resources required to create volume Test2 in storage device b 100B is 1000.

[0088] The volume creation unit 202 determines that volume Test2 should be allocated to storage device b 100B, which has a larger remaining amount of performance resources and can secure the performance resources necessary to create volume Test2. Since DR is not required in this case, the volume creation unit 202 determines that volume Test2 can be allocated to the main site 10A, actually creates the volume, and sets the performance requirements in the QoS unit 112.

[0089] After creating the volume, the volume creation unit 202 adds information to the storage resource management database 240. Fig. 11 shows the update of the storage resource management database 240. Specifically, the value in the Performance Resource consumption column of the storage device b 100B is updated.

[0090] Furthermore, the volume creation unit 202 adds information about the created volume Test2 to the volume information database 230. Fig. 12 shows a state in which information about the new volume Test2 has been added to the volume information database 230, in which information about the existing volume Test1 is registered.

[0091] Next, the processing of the storage management support unit 203 will be described. The storage management support unit 203 alerts the IT administrator's terminal 302 of required or recommended storage facility expansion or volume rebalancing (volume relocation). This allows the IT administrator to know of insufficient performance resources in the storage system. The storage management support unit 203 can execute processing, for example, in response to a request from the IT administrator or periodically.

[0092] If the performance of any storage device is insufficient, the storage management support unit 203 outputs an alert indicating the need for adding or rebalancing (volume relocation) a storage device to the IT administrator's terminal 302. Specifically, the storage management support unit 203 determines whether an alert is necessary based on the performance requirements of the volume assuming that the performance suppression level ρ is not used and the performance resource amount of the storage device.

[0093] 13 shows a flowchart of an example of processing by the storage management support unit 203. Steps S11 to S16 are executed for each storage device at each site. First, the storage management support unit 203 calculates the maximum performance resource amount of the storage device (S41). Furthermore, the storage management support unit 203 calculates the minimum performance resource amount of the storage device (S42).

[0094] Next, the storage management support unit 203 determines whether the minimum performance resource amount exceeds a specified threshold (S43). If the minimum performance resource amount exceeds the specified threshold (S43: YES), the storage management support unit 203 outputs an alert indicating the need for expansion and rebalancing to the terminal 302 (S44).

[0095] If the minimum performance resource amount does not exceed the specified threshold (S43: NO) or after step S44, the storage management support unit 203 determines whether the maximum performance resource amount exceeds the performance resource amount of the storage device (S45). If the maximum performance resource amount exceeds the performance resource amount of the storage device (S45: YES), the storage management support unit 203 outputs an alert indicating the need for expansion and rebalancing to the terminal 302 (S46). If the maximum performance resource amount does not exceed the performance resource amount of the storage device (S45: NO) or after step S46, this flow ends.

[0096] A specific example of the storage management support unit 203 described with reference to Fig. 13 will be described below. First, the calculation S41 of the maximum performance resource amount of the storage device will be described. Here, it is assumed that seven volumes have been created as shown in the volume information database 230 of Fig. 4.

[0097] An example of calculating the maximum performance resource amount for storage device a100A in site A10A will be described. The storage management support unit 203 searches the Actual Storage Apparatus column 236 of the volume information database 230 for volumes allocated to storage device a100A, and finds that "Test1," "Test2," "Test3," "Prod1," and "Prod2" are allocated.

[0098] Next, the storage management support unit 203 obtains the values ​​of the Catalog Name column 232 and the Number of Units column 233 for each volume from the volume information database 230. The storage management support unit 203 obtains the values ​​of the Unit Max Write Throughput column 215 and the Unit Max Read Throughput column 2117 from the row of the corresponding Catalog Name in the service catalog database 210.

[0099] At this time, the storage management support unit 203 compares the α "0.6" and β "0.5" of the storage device a100A with the Unit Max Write Throughput value and the Unit Max Read Throughput value, respectively. The storage management support unit 203 calculates the maximum performance resource amount using the larger value of the Read throughput. The maximum performance resource amount is calculated as α × (Unit Max Read Throughput) × (Number of Units).

[0100] Here, "Test1" is 0.6 x 50 x 60 = 1800. "Test2" is 0.6 x 100 x 20 = 1200. "Test3" is 0.6 x 100 x 20 = 1200. "Prod1" is 0.6 x 100 x 15 = 900. "Prod2" is 0.6 x 100 x 20 = 1200. Therefore, the maximum performance resource amount Umax is 6300.

[0101] Next, the calculation S42 of the minimum performance resource amount of the storage device will be explained. In the above calculation, the minimum performance resource amount can be calculated by using the values ​​in the Unit min Write Throughput column 216 and the Unit min Read Throughput column 218 of the service catalog database 210. The minimum performance resource amount Umin is 5040.

[0102] Next, the comparison S43 between the minimum performance resource amount and the threshold will be explained. The storage management support unit 203 multiplies the value "6000" in the Max Performance Resource column 245 in the row for storage device a100A in the storage resource management database 240 by the threshold "60%" for site A in the site warning threshold management database 250. Then, this integrated value (threshold) is compared with the minimum performance resource amount Umin determined by the above calculation. For storage device a100A, the minimum performance resource amount Umin 5040 is greater than the threshold 3600, so a notification is issued that expansion or rebalancing is necessary. Here, the difference of 1440 is presented as the required expansion amount.

[0103] Next, the comparison S45 between the maximum performance resource amount and the performance resource amount of the storage device will be described. The storage management support unit 203 compares the maximum performance resource amount Umax calculated as described above with the value in the Max Performance Resource column 245 in the row for storage device a in the storage resource management database 240.

[0104] As described above, the maximum performance resource amount Umax is 6300, and the value in the Max Performance Resource column 245 of storage device a100A is 6000. Because 6300 > 6000, the need for expansion or rebalancing is notified. The difference is 300, which is the recommended expansion amount. In this case, the required expansion amount is 1440, and because the required expansion amount is greater than the difference, 1440 is presented as the recommended expansion amount.

[0105] 14 shows an example of an alert image presented on the IT administrator's terminal 302 by the storage management support unit 203. The image shows information about a selected site, and in this case, site A is selected. Section 400 shows the required and recommended expansion amounts of performance resources at site A. As described above, 1440 is presented as the required and recommended expansion amounts for storage device a100A that satisfies the requirement of a response time of 0.1.

[0106] Section 410 shows information about the performance resource amounts of the storage devices at site A. Specifically, graphs 411 and 412 show information about storage device a100A and storage device b100B, respectively. Graphs 411 and 412 show past and calculated values ​​of the maximum required performance resource amount, minimum required performance resource amount, provideable performance resource amount, and changes over time in thresholds. Furthermore, rectangles in graph 411 indicate the period from the start of expansion of storage device a100A to its completion. Furthermore, table 413 shows information about the performance resources of each of storage device a100A and storage device b100B at site A100A.

[0107] An example of a calculation formula that can be used in the above processing by the storage management support unit 203 will be described. The storage management support unit 203 can calculate the maximum performance resource amount U from the volume in the storage device j according to the following formula. Uj, max=Σ i=1 n δij×Pij

[0108] The storage management support unit 203 can calculate the minimum performance resource amount from the volume in storage device j according to the following formula. Uj, min=Σ i=1 n δij×pij

[0109] The storage management support unit 203 can calculate the amount of performance resources that must be increased so that the minimum amount of performance resources does not exceed the threshold, according to the following formula: Note that correction may be made on a volume-by-volume basis. Σ j=1 m max(Uj, min-γjkTj,0) γjk is a threshold value set in the site k where the storage device j is located.

[0110] The storage management support unit 203 can calculate the insufficient performance resource amount of the storage device relative to the maximum performance resource consumption amount according to the following formula: Note that correction may also be made on a volume-by-volume basis. Σ j=1 m max(Uj, max-Tj,0)

[0111] As described above, in this embodiment, when an application engineer uses the remote copy function, the application engineer creates volumes and pairs that meet performance requirements, ensuring that performance degradation does not occur after a failover. Furthermore, even when providing a DR environment, there is no need to uniformly configure the storage, allowing the IT administrator to select the environment that is most appropriate, either an on-premise environment or a cloud environment. [Example]

[0112] An embodiment of this specification will be described below. In this embodiment, before a failover, the remote volume is placed in a storage device different from the storage device under management, and during a failover, the remote volume is relocated to the storage device under management. This allows the remote storage device to be used more efficiently.

[0113] The system configuration in this embodiment is as shown in Figure 1, and it is assumed that site B 10B is a remote site and exists in the cloud. It is also assumed that the storage device of cloud site B 10B has not been initially started. The volume creation unit 202 determines whether it is possible to set QoS according to the performance requirements of the volume at the remote destination, and the timing for actually assigning QoS may be at the time of failover.

[0114] 15A and 15B show flowcharts of a processing example of the volume creation unit 202. Steps S11 to S19 shown in Fig. 15A are the same as those described with reference to Fig. 9A. In Fig. 15B, steps S20 to S24 are the same as those described with reference to Fig. 9B.

[0115] After step S24, the volume creation unit 202 creates a volume at the main site (S51), and further sets the performance requirements of the volume created at the main site in the QoS unit 112 (S52).

[0116] Next, if there is no storage device running at the remote site, the volume creation unit 202 starts one of the storage devices (S53). If multiple storage devices are running at the remote site, the volume creation unit 202 creates a volume by giving priority to the storage device with the least free capacity. If there is insufficient free capacity, a new storage device is started (S54). This makes it possible to reduce power consumption and costs.

[0117] The volume creation unit 202 creates a volume at the remote site and creates a remote copy pair (S54). Next, information about the actual volume is registered in the volume information database 230 (S56), and furthermore, the performance resource consumption amount in the storage resource management database 240 is updated with the actual information (S57).

[0118] Next, the processing of the storage management support unit 203 during failover will be explained. Fig. 16 shows a flowchart of an example of processing of the storage management support unit 203 during failover. When the storage management support unit 203 receives a request from an application engineer, it lists volumes in the volume information database 230 whose managed allocation destinations differ from their actual allocations (S61).

[0119] The storage management support unit 203 starts up the destination storage device if it is not running (S62). The storage management support unit 203 relocates the volumes in the list (S63). The storage management support unit 203 sets QoS for all volumes according to the volume information database 230 (S64). The storage management support unit 203 updates the actual destination of placement in the volume information database 230 (S65). [Example]

[0120] This embodiment determines whether volume performance requirements can be met without expansion by relocating (rebalancing) volumes, and outputs an alert indicating expansion or rebalancing depending on the results of this determination, thereby reducing the burden on IT administrators.

[0121] Fig. 17 shows a flowchart of an example of processing by the storage management support unit 203. Steps S41, S42, S43, and S45 have been described with reference to Fig. 13. In step S43, if the minimum performance resource amount exceeds the threshold (S43: YES), the storage management support unit 203 determines whether the state will be resolved by rebalancing (S71). If the performance resource shortage is not resolved by rebalancing (S71: NO), the storage management support unit 203 outputs an alert indicating expansion (S72), and if the performance resource shortage is resolved by rebalancing (S71: YES), the storage management support unit 203 outputs an alert indicating rebalancing (S73).

[0122] In step S45, if the maximum performance resource amount exceeds the performance resource amount of the storage device (S45: YES), the storage management support unit 203 determines whether the state will be resolved by rebalancing (S74). If the performance resource shortage is not resolved by rebalancing (S74: NO), the storage management support unit 203 outputs an alert indicating expansion (S75), and if the performance resource shortage is resolved by rebalancing (S74: YES), the storage management support unit 203 outputs an alert indicating rebalancing (S76).

[0123] A method for determining whether rebalancing can resolve the performance resource shortage is explained below. The storage management support unit 203 determines whether rebalancing is possible based on the information in the service catalog database 210, storage resource management database 240, volume information database 230, and site warning threshold management database 250 in the following manner.

[0124] First, the rebalancing determination S71 when the minimum performance resource amount exceeds the threshold will be described. Fig. 18 shows a flowchart of the rebalancing determination when the minimum performance resource amount exceeds the threshold. The storage management support unit 203 executes steps S81 to S85 for each site.

[0125] The storage management support unit 203 creates a list of volumes located at a site from the volume information database 230, for each defined response time (S81). The storage management support unit 203 sorts the volumes in the list in descending order of the defined minimum throughput requirement (S82). The storage management support unit 203 creates a separate list of storage devices that can meet the response time for each list (S83).

[0126] The storage management support unit 203 executes steps S84 and S85 within each list that satisfies the response time. The storage management support unit 203 determines whether the minimum throughput requirement of the volume can be allocated within the performance resource amount threshold of each storage device in the storage device list (S84).

[0127] If allocation is possible (S84: YES), the storage management support unit 203 selects and allocates the storage device with the smallest remaining performance resource amount threshold from among the allocatable storage devices (S85).Uj / max(αj, βj) takes into account the characteristics of each storage device.

[0128] If allocation is not possible (S84: NO), the storage management support unit 203 ends the process at that point and determines that rebalancing is not possible. If the processes from steps S81 to S85 are completed to the end, the storage management support unit 203 determines that rebalancing is possible (S86).

[0129] Next, the rebalancing determination S74 when the maximum performance resource amount exceeds the performance resource amount of the storage device will be described. Fig. 19 shows a flowchart for determining rebalancing when the maximum performance resource amount exceeds the performance resource amount of the storage device. The storage management support unit 203 executes steps S91 to S95 for each site.

[0130] The storage management support unit 203 creates a list of volumes for each defined response time from the volume information database 230 (S91). The storage management support unit 203 sorts the volumes in the list in descending order of the defined maximum throughput requirement (S92). The storage management support unit 203 creates a separate list of storage devices that can meet the response time for each list (S93).

[0131] The storage management support unit 203 executes steps S94 and S95 within each list that satisfies the response time. The storage management support unit 203 determines whether the maximum throughput requirement of the volume can be allocated within the performance resource amount of each storage device in the storage device list (S94).

[0132] If allocation is possible (S94: YES), the storage management support unit 203 selects and allocates the storage device with the smallest remaining amount of performance resources from among the allocatable storage devices (S95).Uj / max(αj, βj) takes into account the characteristics of each storage device.

[0133] If allocation is not possible (S94: NO), the storage management support unit 203 ends the process at that point and determines that rebalancing is not possible (S97). If the processes from steps S91 to S95 are completed to the end, the storage management support unit 203 determines that rebalancing is possible (S96).

[0134] Here, an example of determining whether a performance resource shortage can be resolved by rebalancing will be described. Assume that a performance resource shortage occurs in storage device c 100C. First, in site B 100B, in order to list volumes for each response time registered in the volume information database 230, the storage management support unit 203 obtains the response time requirements for the volumes located in site B 100B.

[0135] The storage management support unit 203 obtains the P99 Response Time of the Catalog Name row of the service catalog database 210 from the Catalog Name column 232 of the volume information database 230, and lists it by "0.1 m / s" and "10 m / s." Here, "0.1 m / s" includes "Prod2" and "Prod3," and "10 m / s" includes "Prod1" and "Prod4."

[0136] The storage management support unit 203 sorts the "0.1 m / s" list in descending order of minimum throughput requirement. Here, "Prod2" is 1280 and "Prod3" is 2560, so the storage management support unit 203 sorts in the order "Prod3" and "Prod2". Similarly, for "10 m / s," "Prod1" is 960 and "Prod4" is 560, so the storage management support unit 203 sorts in this order.

[0137] Here, the storage management support unit 203 checks, in sorted order, whether volumes in the list can be allocated to storage device "c" that can meet the response time requirement of "0.1 m / s." First, "Prod3" can be allocated because the performance resource amount of storage device "c" is 3850. Next, "Prod2" can be allocated because the remaining performance resource amount of storage device "c" is 3850-2560=1290. Here, the remaining performance resource amount is 1290-1280=10.

[0138] Next, the storage management support unit 203 checks in sorted order whether volumes in the list can be allocated in storage devices "c" and "d" that can satisfy the response time of "10 m / s."

[0139] First, "Prod1" is allocated to storage device "d" because the remaining performance resource capacity of storage device "c" is 10 and the remaining performance resource capacity of storage device "d" is 1750. Next, "Prod4" is allocated to storage device "d" because the remaining performance resource capacity of storage device "c" is 10 and the remaining performance resource capacity of storage device "d" is 1750-960=790. Here, the remaining performance resource capacity of storage device "d" is 790-560=230.

[0140] Here, since the volumes were able to be relocated to the end, it is determined that rebalancing is effective. The storage management support unit 203 has determined from the above calculation that the alert will be cleared by relocating "Prod1", which was located in storage device "c", to storage device "d", and therefore proposes rebalancing to the IT administrator via the GUI.

[0141] 20 shows an example of an alert image presented on the IT administrator's terminal 302 by the storage management support unit 203. The image shows information about a selected site, and in this case, site B is selected. Section 500 shows the required and recommended expansion amounts of performance resources at site B. 950 is presented as the required and recommended expansion amounts for storage device c100C, which satisfies the requirement of a response time of 0.1.

[0142] Section 520 shows information about recommended rebalancing, which suggests moving (relocating) volume Prod1 from the current storage device c100C to another storage device d100D.

[0143] Section 410 shows information on the performance resource amounts of the storage devices at site B. Specifically, graphs 511 and 512 show information on storage devices c100C and d100D, respectively. Graphs 511 and 512 show past and calculated values ​​of the maximum required performance resource amount, minimum required performance resource amount, provideable performance resource amount, and changes over time in thresholds. Furthermore, rectangles in graph 511 indicate the period from the start of volume relocation (rebalancing) to the completion of expansion. Table 513 shows performance resource information for each of storage devices c100C and d100D at site B100B.

[0144] The above-described embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to a configuration including all of the described configurations. It is possible to replace part of the configuration of the embodiment with another configuration. It is also possible to delete part of the configuration of the embodiment.

[0145] Furthermore, some or all of the above-described units, configurations, functions, processing units, etc. may be implemented in hardware, for example, by designing them as integrated circuits. Furthermore, the above-described units, configurations, functions, etc. may be implemented in software by a processor interpreting and executing a program that implements each function. Information such as the programs, tables, and files that implement each function can be stored in a memory, a recording device such as a hard disk, or a storage medium such as an IC card, SD card, or DVD.

[0146] It should be noted that the control lines and information lines in the above-described embodiments are those considered necessary for the explanation, and do not necessarily show all the control lines and information lines in the product. In reality, it can be considered that almost all components are interconnected. The present invention has been described above, focusing on the embodiments. [Explanation of symbols]

[0147] 10A Site A 10B Site B 100A Storage device a 100B Storage device b 100C Storage device 100D Storage Device 111 Remote Copy Unit 112 QoS section 200 Storage operation management server 201 Service Catalog Interface Unit 202 Volume Creation Section 203 Storage Management Support Department 210 Service Catalog Database 230 Volume Information Database 240 Storage Resource Management Database 250 Site Warning Threshold Management Database

Claims

1. An apparatus for managing a storage system, comprising: a processor; a storage device, The storage device storing storage resource management information for managing information on throughput performance resources and response times of storage devices at the main site and the remote site; The processor: receiving performance requirements, including response performance and throughput performance, for a volume copy pair consisting of a primary volume at the main site and a secondary volume at the remote site; referring to the storage resource management information to determine whether there are storage devices at both the main site and the remote site that satisfy the performance requirements; A device that determines to create the volume copy pair when a storage device that satisfies the performance requirements exists at both the main site and the remote site.

2. 10. The apparatus of claim 1, The processor sets upper and lower limits of throughput performance for each volume of the volume copy pair for the storage devices at the main site and the remote site when creating the volume copy pair.

3. 10. The apparatus of claim 1, the storage device stores volume management information for managing volumes located at the main site and the remote site; the volume management information manages the storage device that is the administrative destination of the volume that is located at the remote site and the storage device that is the actual destination of the volume; the management destination storage device satisfies the performance requirements, The processor, in the event of a failover by the secondary volume, relocates the secondary volume to the managed destination storage device, and sets upper and lower limits for the throughput performance of the secondary volume in the managed destination storage device.

4. 10. The apparatus of claim 1, When the total requested upper limit performance of volumes to be placed in a storage device exceeds the performance resource amount of the storage device, the processor restricts the upper limit performance of the volumes from the requested upper limit performance so that the total upper limit performance of the volumes is equal to or less than the performance resource amount.

5. 5. The apparatus of claim 4, The processor determines an upper limit performance constraint for each of the volumes using combinatorial optimization.

6. 5. The apparatus of claim 4, The processor outputs an alert when the total of the required upper limit performance of the volumes arranged in the storage device exceeds the performance resource amount of the storage device.

7. 5. The apparatus of claim 4, The apparatus, wherein the processor outputs an alert indicating the relocation when the constraint can be resolved by relocating the volume between storage devices within one site.

8. 8. The apparatus of claim 7, The processor outputs an alert indicating an expansion if the constraint cannot be resolved by the rearrangement.

9. A method for managing a storage system by an apparatus, comprising: The device stores storage resource management information for managing information on throughput performance resources and response times of storage devices at the main site and the remote site; The method further comprises the steps of: receiving performance requirements, including response performance and throughput performance, for a volume copy pair consisting of a primary volume at the main site and a secondary volume at the remote site; referring to the storage resource management information to determine whether there are storage devices at both the main site and the remote site that satisfy the performance requirements; A method for determining to create the volume copy pair when a storage device that satisfies the performance requirements exists at both the main site and the remote site.

Images