Storage system, battery refreshment method in storage system, and program

Abstract

To provide a storage system that enables battery refreshment while maintaining high data integrity.SOLUTION: A storage control part performs a notification of a battery refreshment request of a battery within a controller including the storage control part. A storage system monitoring part responds to the battery refreshment request from the storage control part and distributes loads relating to data processing to a storage other than the storage with the battery refreshment request. A storage control part (114) discharges the battery based on a power amount required for evacuating data on a cache memory to a nonvolatile area, and then performs battery refreshment of the battery.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a storage system, a battery refresh method in a storage system, and a program. [Background technology]

[0002] Advances in information technology have dramatically increased the amount of information handled. This has led to a growing need for high-capacity, high-density storage systems. Data handling in these storage systems is generally managed by a file system. While writing data to a disk drive is necessary, temporary processing is performed using cache memory, which is installed within the storage system and includes the disk drive, to ensure performance. If the power supply is interrupted while using cache memory, the data in the cache memory may be lost. Therefore, it is common to install a battery and back up the data to non-volatile memory to prevent data loss. Furthermore, because storage systems must operate 24 hours a day, 365 days a year, depending on the operating environment, they must constantly retain the data in the cache memory, so battery capacity is maintained at a high level.

[0003] However, in devices that use batteries as a power source, repeated shallow charging and discharging can cause a memory effect, which reduces the battery's operating time. To prevent this, a process called battery refresh is generally required to release excess charge stored in the battery and restore normal battery operation.

[0004] For example, Patent Document 1 discloses a technique for determining that battery refresh is necessary and automatically performing battery refresh when it is determined that battery refresh is necessary. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-328624 Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 discloses a technology for automatically performing battery refresh. However, with the technology disclosed in Patent Document 1, if a power outage occurs during battery refresh in a storage device included in a storage system, there is no data to retain, or it is necessary to stop data retention for the storage device during battery refresh, or to reduce data retention and risk data loss.

[0007] Furthermore, battery refresh requires complete discharge. Therefore, in storage devices that use large-capacity batteries, the battery capacity is maintained at a high level, so discharging takes time. Therefore, in devices such as storage systems that require constant operation, battery refresh is difficult from the perspective of preventing data loss.

[0008] An object of the present disclosure is to provide a storage system, a battery refresh method in a storage system, and a program that solves the above-mentioned problems. [Means for solving the problem]

[0009] A storage system according to one aspect of the present disclosure comprises a plurality of storages, each having a controller including a battery, a cache memory, a non-volatile area, and a storage control unit, and a storage system monitoring unit that controls the plurality of storages, wherein the storage control unit notifies a battery refresh request for the battery in the controller that includes the storage control unit, the storage system monitoring unit responds to the battery refresh request from the storage control unit and distributes the load related to data processing to storages other than the storage that has the battery refresh request, and the storage control unit in the controller that made the battery refresh request discharges the battery of the controller that includes the storage control unit based on the amount of power required to save data in the cache memory of the controller to the non-volatile area, and then causes the battery to be refreshed.

[0010] A battery refresh method in a storage system according to one aspect of the present disclosure is applied to a storage system having a plurality of storages, each having a controller including a battery, a cache memory, a non-volatile area, and a storage control unit, and a storage system monitoring unit that controls the plurality of storages, wherein the storage control unit notifies a battery refresh request for the battery in the controller that includes the storage control unit, the storage system monitoring unit responds to the battery refresh request from the storage control unit and distributes the load related to data processing to storages other than the storage that has the battery refresh request, and the storage control unit in the controller that made the battery refresh request discharges the battery of the controller that includes the storage control unit based on the amount of power required to save data in the cache memory of the controller to the non-volatile area, and then causes the battery to be refreshed.

[0011] A program according to one aspect of the present disclosure causes a computer for a storage system having a plurality of storages, each having a controller including a battery, a cache memory, a non-volatile area, and a storage control unit, and a storage system monitoring unit that controls the plurality of storages, to perform the following operations: notifying, by the storage control unit, a battery refresh request for the battery in the controller that includes the storage control unit; responding, by the storage system monitoring unit, to the battery refresh request of the storage control unit and distributing the load related to data processing to storages other than the storage that has requested the battery refresh; and discharging, by the storage control unit in the controller that made the battery refresh request, the battery of the controller that includes the storage control unit based on the amount of power required to save data in the cache memory of the controller to the non-volatile area, and then causing a battery refresh of the battery. [Effects of the Invention]

[0012] According to the above aspect, in the storage system, it becomes possible to perform battery refresh in a state where data integrity is high. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram illustrating a configuration of a storage system according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a diagram illustrating an operation of the storage system during battery refresh. [Figure 3] FIG. 10 is a diagram illustrating an operation of the storage system during battery refresh. [Figure 4] FIG. 1 is a diagram illustrating an example of the configuration of a storage system according to an embodiment of the present disclosure. [Figure 5] 2 is a block diagram showing an example of the hardware configuration of a storage control unit, a battery control unit, and a storage system monitoring unit in a storage system. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Each embodiment will be described below with reference to the drawings. In all drawings, the same or corresponding components are designated by the same reference numerals, and common descriptions will be omitted.

[0015] 1 is a block diagram showing the configuration of a storage system (100) according to an embodiment of the present disclosure. The storage system (100) comprises multiple storages (110, 130, 131) with a redundant configuration and a storage system monitor (140). The multiple storages (110, 130, 131) and the storage system monitor (140) are connected via a network.

[0016] Each storage (110, 130, 131) has two internal storage devices and two internal controllers (111, 121;...), providing a redundant configuration. Each controller (111, 121;...) is equipped with a battery (113, 123;...), a cache memory (115, 125;...), and a non-volatile area (116, 126;...), each of which is paired to ensure data integrity. Furthermore, each controller (111, 121;...) is equipped with a battery control unit (112, 122;...) and a storage control unit (114, 124;...).

[0017] Here, the cache memory (115, 125;...) is used to temporarily store data in order to ensure performance such as write speed. The battery (113, 123;...) supplies power to save data in the cache memory (115, 125;...) to the non-volatile area (116, 126;...) to prevent data loss in case the power supply is interrupted when the cache memory (115, 125;...) is being used. While the data in the cache memory (115, 125;...) is being saved to the non-volatile area (116, 126;...), the battery (113, 123;...) supplies power to operate only the minimum number of devices.

[0018] The battery control units (112, 122;...) monitor the power capacity of the batteries (113, 123;...) and control the charging and discharging of the batteries (113, 123;...). The storage control units (114, 124;...) manage the timing of battery refresh for the batteries (113, 123;...) in the controllers (111, 121;...) that include the storage control units (114, 124;...) and cause the battery refresh to be performed. Furthermore, in the event of an interruption in the power supply, the storage control units (114, 124;...) use power supplied from the batteries (113, 123;...) to retain data in the cache memories (115, 125;...) and to save the data in the cache memories (115, 125;...) to the non-volatile areas (116, 126;...).

[0019] The cache memory (115, 125;...) is composed of RAM (Random Access Memory) which allows high-speed access. The non-volatile area (116, 126;...) is composed of EEPROM (Electrically Erasable Programmable Read-Only Memory). The storage device is composed of large-capacity storage devices such as disk drives, SSDs (Solid State Drives), and magnetic tape drives.

[0020] The storage system (100) shown in FIG. 1 includes three storages (110, 130, 131) as an example, but is not limited to this and may include two or more storages.

[0021] Next, the operation of a storage system (100) constructed by incorporating multiple storages with redundant configurations will be described. Figures 2 and 3 are diagrams showing the operation during battery refresh of a battery in a controller. Here, an example will be described in which a battery refresh of the battery (113) in the controller (111) of the storage (110) constituting the storage system (100) is required. Therefore, the operation related to battery refresh in the battery control unit (112), storage control unit (114), and storage system monitoring unit (140) in the controller (111) will be described with reference to Figures 2 and 3. The battery control units and storage control units in the other controllers also operate in the same way.

[0022] As shown in FIG. 2, in the storage 110, the battery control unit 112 in the controller 111 periodically acquires the remaining battery charge of the internal battery 113 (S1-1) and determines whether the battery is being charged (S1-2). If the battery is not being charged (S1-2: No), the battery control unit 112 returns to step S1-1 for the next remaining battery charge check. If the battery is being charged (S1-2: Yes), the battery control unit 112 checks the number of charges (S1-3). If the number of charges does not exceed a predetermined number (S1-4: No), the battery control unit 112 returns to step S1-1 for the next remaining battery charge check. If the number of charges exceeds a predetermined number (S1-4: Yes), the battery control unit 112 determines that battery refresh is required and sets a battery refresh request flag (S1-5).

[0023] The storage control unit 114 checks at predetermined intervals whether the battery refresh request flag is set (S2-1). If the flag is not set (S2-1: No), the storage control unit 114 proceeds to the next flag check (S2-1). If the flag is set (S2-1: Yes), the storage control unit 114 notifies the storage system monitor 140, which monitors the entire storage system 100, of a battery refresh request along with information identifying the controller that made the battery refresh request (S2-2).

[0024] Upon receiving the battery refresh request notification, the storage system monitoring unit (140) plans a battery refresh schedule for the storage in question based on the load status of the entire storage system (100) (S3-1). Here, "load" refers to the amount of data written to the entire storage system (100) or the amount of processing required for that data.

[0025] The storage system monitoring unit 140 distributes the load from the storage device 110 undergoing battery refresh to the other storage devices 130 / 131 (S3-2). This reduces the amount of data in the cache memory 115 that must be saved when a power outage occurs in the storage device 110 undergoing battery refresh. Reducing the load on the storage device undergoing battery refresh ultimately means that the storage devices not undergoing battery refresh also bear the load that the storage device undergoing battery refresh should bear. Therefore, the storage system monitoring unit 140 maintains a log of the load on the entire storage system 100 and, based on past performance, particularly recent performance, plans a battery refresh schedule for a time period that reduces the load on some storage devices through battery refresh without placing an excessive load on other storage devices. Furthermore, when planning the battery refresh schedule, the storage system monitoring unit 140 plans it to be performed by one controller per storage device to ensure data integrity in the system when the power supply is interrupted during battery refresh. That is, when battery refresh requests are received from both controllers in the same storage, the storage system monitoring unit (140) plans to prevent the battery refresh from being performed simultaneously, and to perform the battery refresh of one controller after the battery refresh of the other controller is completed.

[0026] As described above, by distributing the load from the storage device (110) undergoing battery refresh to the other storage devices (130 / 131), data stored in the cache memory (115) of the storage device (110) undergoing battery refresh is suppressed. If there is less data stored in the cache memory, the time required to write the data to the non-volatile area (116) paired with the cache memory (115) can be shortened. As a result, even if the power supply is interrupted, less battery capacity needs to be reserved to save data in the non-volatile area (116). Although the battery refresh requires the battery to be completely discharged, the battery refresh can be completed in a short time while avoiding the risk of power supply being interrupted during the battery refresh.

[0027] 3, the storage control unit (114) checks the amount of data in the cache memory (115), and each time the amount of data decreases by a certain percentage, calculates the remaining battery capacity required to store the data in the nonvolatile storage area (116) in accordance with the amount of data (S2-3). Here, the "required remaining battery capacity" refers to the battery capacity of the battery (113) required for the controller (111) to save the data in the cache memory (115) to the nonvolatile storage area (116) in the event of a power outage. The storage control unit (114) notifies the battery control unit (112) of the calculated remaining battery capacity (S2-4).

[0028] The battery control unit 112 discharges the battery 113 until the remaining battery charge reaches the notified amount (S1-6). When the discharge of the battery 113 is completed to the notified amount (S1-7: Yes), the battery control unit 112 notifies the storage control unit 114 of the completion of the discharge (S1-8).

[0029] The storage control unit (114) may check the amount of data in the cache memory (115) after a predetermined time has elapsed since the load balancing by the storage system monitoring unit (140). This allows the storage control unit (114) to start processing related to battery refresh after the amount of data in the cache memory (115) has decreased. Alternatively, the storage control unit (114) may check the amount of data in the cache memory (115) at predetermined cycles, and when the amount of data falls below a predetermined amount or the required remaining battery power falls below a predetermined value, notify the battery control unit (112) of the calculated remaining battery power (S2-4). Alternatively, the processing of (S2-3), (S2-4), and (S1-6) to (S1-8) shown in FIG. 3 may be repeated until the amount of data in the cache memory (115) falls below a predetermined amount or the required remaining battery power falls below a predetermined value.

[0030] After receiving the notification of the completion of discharge before the battery refresh, the storage control unit (114) instructs the battery control unit (112) to perform the battery refresh (S2-5).

[0031] After receiving the instruction from the storage control unit 114, the battery control unit 112 starts a battery refresh of the battery 113 (S1-9). After the battery refresh completes the full discharge, the battery control unit 112 charges the battery 113 to its specified capacity (S1-10). When charging to the specified capacity is completed, the battery control unit 112 turns off the battery refresh request flag (S1-11).

[0032] The storage control unit 114 checks whether the battery refresh request flag for the battery 113 is cleared (S2-6). If the battery refresh request flag is cleared (S2-6: Yes), the storage control unit 114 notifies the storage system monitoring unit 140 of the completion of the battery refresh in the controller 111 together with the identification information of the controller that notified the completion (S2-7).

[0033] Upon receiving the notification of the completion of the battery refresh, the storage system monitor (140) returns the distributed load in the storage system (100) to its original state (S3-3).

[0034] If the power supply is interrupted during battery refresh, while the battery refresh is being performed on the redundant controller side of the storage during battery refresh, for example, the controller (111), the battery (123) installed on the controller (121) side is used to maintain a state in which data in the cache memory (125) can be saved to the non-volatile area (126). In this case, the redundancy of the storage (110) alone is reduced, but data preservation can be ensured for the entire system.

[0035] As described above, in a storage system (100) incorporating multiple storage units with redundant components, by automatically setting a battery refresh schedule, it is possible to perform battery refresh without the user being aware of it.

[0036] Furthermore, by reducing the load on the storage that performs the battery refresh, it is possible to shorten the battery refresh time and perform the battery refresh in a state where data integrity is high.

[0037] The storage system monitor 140 may set the battery refresh schedule as follows.

[0038] 1. Multiple recommended battery refresh schedule patterns are presented to the user based on past, especially recent, load conditions, allowing the user to select an implementation pattern. The storage system monitoring unit (140) then performs battery refresh according to the selected schedule. This eliminates the need for the user to formulate a battery refresh schedule, and enables battery refresh to be performed according to a schedule that takes into account the user's understanding of the expected future load conditions of the storage system (100).

[0039] 2. If the load becomes high during load balancing for battery refresh, the battery refresh is rescheduled and performed again when the load becomes lower. This prevents storage that does not perform battery refresh due to load balancing from being overloaded more than necessary. If the load becomes high with a predetermined frequency during load balancing, the storage system monitoring unit (140) may notify the user that it is desirable to expand the number of storages in the configuration to N.

[0040] In the present disclosure, the operation of the embodiment has been described to reduce the time required for battery refresh by suppressing data in the cache memory before battery refresh and reducing the area to be backed up. In addition to this, or instead of this, if multiple cache memories are installed in the controller, the storage control unit in the controller may reduce the power consumption of the entire storage by stopping the supply of power to some of the cache memories, for example, cache memories that no longer store data, when the suppression of data in the cache memories has been suppressed to a certain amount or more, and perform battery refresh.

[0041] As described above, the storage system (100) of the present disclosure can perform battery refresh without interruption in a storage system that operates 24 hours a day, 365 days a year.

[0042] 4 is a diagram illustrating an example configuration of a storage system (100) according to an embodiment of the present disclosure. The storage system (100) includes multiple storages (110, 130, ...), each including a controller (111) including a battery (113), a cache memory (115), a non-volatile area (116), and a storage control unit (114), and a storage system monitor (140) that controls the multiple storages (110, 130). The storage control unit (114) issues a battery refresh request for the battery (113) in the controller (111) that includes the storage control unit (114). The storage system monitor (140) responds to the battery refresh request from the storage control unit (114) and distributes the data processing load to the storages (130, ...) other than the storage (110) that has requested the battery refresh. A storage control unit (114) in the controller (111) that has issued the battery refresh request discharges the battery (113) of the controller (111) that includes the storage control unit (114) based on the amount of power required to save data in a cache memory (115) of the controller (111) to a non-volatile area (116), and then causes the battery (113) to be refreshed.

[0043] 5 is a block diagram showing an example of the hardware configuration of the storage control unit 114, battery control unit 112, and storage system monitoring unit 140 in the storage system 100. The hardware configuration of the storage control unit 114, battery control unit 112, and storage system monitoring unit 140 includes a CPU 11, RAM (Random Access Memory) 12, ROM (Read Only Memory) 13, and storage device 14. The ROM 13 and storage device 14 store programs and information that implement the functions of the storage control unit 114, battery control unit 112, and storage system monitoring unit 140. The RAM 12 is used as a working area for temporarily storing data used by the CPU 11 and other components during operation. The storage control unit 114, the battery control unit 112, and the storage system monitoring unit 140 each include an input / output port 15 for connecting to other devices, such as a cache memory 115 or a non-volatile storage area 116 in the storage control unit 114. The input / output port 15 may also be an input / output port for connecting an input / output device such as a keyboard, a mouse, or a display device to the storage system monitoring unit 140. The ROM 13 may be configured as an EEPROM (Electrically Erasable Programmable Read-Only Memory) or the like, and the recording device 14 may be configured as a hard disk, SSD, or the like, and computer programs for implementing the functions of the storage control unit 114, the battery control unit 112, and the storage system monitoring unit 140 may be updated in the ROM 13 or the recording device 14. The storage control unit 114 and the battery control unit 112 may be configured as separate hardware, or may be configured as common hardware with their functions implemented separately by software.

[0044] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0045] Some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes.

[0046] (Appendix 1) a plurality of storages each including a controller including a battery, a cache memory, a non-volatile area, and a storage control unit; a storage system monitoring unit that controls the plurality of storages, the storage control unit notifies a battery refresh request for the battery in the controller including the storage control unit; the storage system monitoring unit responds to the battery refresh request from the storage control unit and distributes the load related to data processing to storages other than the storage that has requested the battery refresh; the storage control unit in the controller that has issued the battery refresh request discharges the battery of the controller that includes the storage control unit based on the amount of power required to save the data in the cache memory of the controller to the non-volatile area, and then causes the battery to be refreshed; Storage system.

[0047] (Appendix 2) the storage is provided with two or more of the controllers; when the storage system monitoring unit detects storage refresh requests from the plurality of controllers in the same storage, it schedules battery refresh so that the plurality of controllers in the same storage that have made battery refresh requests do not simultaneously perform battery refresh; 2. The storage system of claim 1.

[0048] (Appendix 3) the controller further includes a battery control unit that controls a remaining capacity of the battery in the controller; the storage control unit that has notified the battery refresh request calculates the amount of power required to save data to the non-volatile area in accordance with the decrease in the amount of data in the cache memory in the controller included in the storage control unit, and notifies the battery control unit of the amount of power required; the battery control unit controls the battery to discharge up to the notified amount of power, and then performs a battery refresh on the battery. 3. The storage system of claim 1 or 2.

[0049] (Appendix 4) the storage system monitoring unit stops the load distribution when the load reaches or exceeds a predetermined value during the load distribution; 4. The storage system of claim 1.

[0050] (Appendix 5) the controller includes a plurality of cache memories; the storage control unit that has requested the battery refresh further performs control to stop power supply to a cache memory that does not store the data during the battery refresh process; 5. The storage system of claim 1.

[0051] (Appendix 6) the storage system monitoring unit determines a plurality of schedules for distributing the load related to data processing to the plurality of storages based on past load conditions in the storage system, and distributes the load based on a schedule selected by a user from the plurality of schedules; 6. The storage system of any one of appendixes 1 to 5.

[0052] (Appendix 7) the storage system monitoring unit ends the load balancing in response to a notification of completion of the battery refresh from the storage control unit that made the battery refresh request. 7. The storage system of any one of appendixes 1 to 6.

[0053] (Appendix 8) the battery control unit issues the notification of the battery refresh request when the number of times the battery of the controller including the battery control unit has been charged reaches a predetermined number of times or more. 4. The storage system of claim 3.

[0054] (Appendix 11) a plurality of storages each including a controller including a battery, a cache memory, a non-volatile area, and a storage control unit; a storage system monitoring unit that controls the plurality of storages, notifying, by the storage control unit, a battery refresh request for the battery in the controller including the storage control unit; the storage system monitoring unit responds to the battery refresh request from the storage control unit, distributing the load related to data processing to storages other than the storage that has requested the battery refresh; the storage control unit in the controller that has issued the battery refresh request discharges the battery of the controller that includes the storage control unit based on the amount of power required to save the data in the cache memory of the controller to the non-volatile area, and then causes the battery to be refreshed; A battery refresh method in a storage system.

[0055] (Appendix 12) the storage is provided with two or more of the controllers; when the storage system monitoring unit detects storage refresh requests from a plurality of the controllers in the same storage, it schedules battery refresh so that the plurality of controllers in the same storage that have made battery refresh requests do not simultaneously perform battery refresh; A battery refresh method in the storage system described in Appendix 11.

[0056] (Appendix 13) the controller further includes a battery control unit that controls a remaining capacity of the battery in the controller; the storage control unit that notified the battery refresh request calculates the amount of power required to save data in the non-volatile area in accordance with the reduction in the amount of data in the cache memory in the controller included in the storage control unit, and notifies the battery control unit of the amount of power calculated; the battery control unit controls the battery to discharge up to the notified amount of power, and then performs a battery refresh on the battery. A battery refresh method in a storage system according to claim 11 or 12.

[0057] (Appendix 14) When the load exceeds a predetermined value during the load distribution by the storage system monitoring unit, the load distribution is stopped. A battery refresh method in a storage system according to any one of appendices 11 to 13.

[0058] (Appendix 15) the controller includes a plurality of cache memories; The storage control unit that has issued the battery refresh request further controls to stop power supply to a cache memory that does not store the data during the battery refresh process. A battery refresh method in a storage system according to any one of appendices 11 to 14.

[0059] (Appendix 16) The storage system monitoring unit determines a plurality of schedules for distributing the load related to data processing to the plurality of storages based on the past load status of the storage system, and distributes the load based on a schedule selected by a user from the plurality of schedules. A battery refresh method in a storage system according to any one of appendices 11 to 15.

[0060] (Appendix 17) the storage system monitoring unit ends the load distribution in response to a notification of completion of the battery refresh from the storage control unit that made the battery refresh request. A battery refresh method in a storage system according to any one of appendices 11 to 16.

[0061] (Appendix 18) When the number of times of charging the battery of the controller including the battery control unit reaches or exceeds a predetermined number, the battery control unit issues a notification of the battery refresh request. A battery refresh method in the storage system described in Appendix 13.

[0062] (Appendix 21) a plurality of storages each including a controller including a battery, a cache memory, a non-volatile area, and a storage control unit; a storage system monitoring unit that controls the plurality of storages, notifying, by the storage control unit, a battery refresh request for the battery in the controller including the storage control unit; the storage system monitoring unit responds to the battery refresh request from the storage control unit, distributing the load related to data processing to storages other than the storage that has requested the battery refresh; the storage control unit in the controller that has issued the battery refresh request discharges the battery of the controller that includes the storage control unit based on the amount of power required to save the data in the cache memory of the controller to the non-volatile area, and then causes the battery to be refreshed; A program to make it happen.

[0063] (Appendix 22) the storage is provided with two or more of the controllers; when the storage system monitoring unit detects storage refresh requests from a plurality of the controllers in the same storage, it schedules battery refresh so that the plurality of controllers in the same storage that have made battery refresh requests do not simultaneously perform battery refresh; 22. The program of claim 21, further comprising:

[0064] (Appendix 23) the controller further includes a battery control unit that controls a remaining capacity of the battery in the controller; the storage control unit that notified the battery refresh request calculates the amount of power required to save data in the non-volatile area in accordance with the reduction in the amount of data in the cache memory in the controller included in the storage control unit, and notifies the battery control unit of the amount of power calculated; the battery control unit controls the battery to discharge up to the notified amount of power, and then performs a battery refresh on the battery. 23. The program according to claim 21 or 22, further comprising:

[0065] (Appendix 24) When the load exceeds a predetermined value during the load distribution by the storage system monitoring unit, the load distribution is stopped. 24. The program according to any one of appendices 21 to 23, further comprising:

[0066] (Appendix 25) the controller includes a plurality of cache memories; The storage control unit that has issued the battery refresh request further controls to stop power supply to a cache memory that does not store the data during the battery refresh process. 25. The program according to any one of appendices 21 to 24, further comprising:

[0067] (Appendix 26) The storage system monitoring unit determines a plurality of schedules for distributing the load related to data processing to the plurality of storages based on the past load status of the storage system, and distributes the load based on a schedule selected by a user from the plurality of schedules. 26. The program according to any one of appendices 21 to 25, further comprising:

[0068] (Appendix 27) the storage system monitoring unit ends the load distribution in response to a notification of completion of the battery refresh from the storage control unit that made the battery refresh request. 27. The program according to any one of appendices 21 to 26, further comprising:

[0069] (Appendix 28) When the number of times of charging the battery of the controller including the battery control unit reaches or exceeds a predetermined number, the battery control unit issues a notification of the battery refresh request. 24. The program of claim 23, further comprising: [Explanation of symbols]

[0070] 100 Storage Systems 110,130,131 Storage 110 Storage 111 Controller 112 Battery control unit 113 Battery 114 Storage control section 115 cache memory 116 Non-volatile area 121 Controller 123 Battery 125 cache memory 126 Non-volatile area 130 Storage 131 Storage 140 Storage System Monitoring Department

Claims

1. a plurality of storages each including a controller including a battery, a cache memory, a non-volatile area, and a storage control unit; a storage system monitoring unit that controls the plurality of storages, the storage control unit notifies a battery refresh request for the battery in the controller including the storage control unit; the storage system monitoring unit responds to the battery refresh request from the storage control unit and distributes the load related to data processing to storages other than the storage that has requested the battery refresh; the storage control unit in the controller that has issued the battery refresh request discharges the battery of the controller that includes the storage control unit based on the amount of power required to save the data in the cache memory of the controller to the non-volatile area, and then causes the battery to be refreshed; Storage system.

2. the storage is provided with two or more of the controllers, when the storage system monitoring unit detects storage refresh requests from the plurality of controllers in the same storage, it schedules battery refresh so that the plurality of controllers in the same storage that have made battery refresh requests do not simultaneously perform battery refresh; The storage system according to claim 1 .

3. the controller further includes a battery control unit that controls a remaining capacity of the battery in the controller; the storage control unit that has notified the battery refresh request calculates the amount of power required to save data to the non-volatile area in accordance with the decrease in the amount of data in the cache memory in the controller included in the storage control unit, and notifies the battery control unit of the amount of power required; the battery control unit controls the battery to discharge up to the notified amount of power, and then performs a battery refresh on the battery. The storage system according to claim 1 .

4. the storage system monitoring unit stops the load distribution when the load reaches or exceeds a predetermined value during the load distribution; The storage system according to claim 1 .

5. the controller includes a plurality of cache memories; the storage control unit that has requested the battery refresh further performs control to stop power supply to a cache memory that does not store the data during the battery refresh process; The storage system according to claim 1 .

6. the storage system monitoring unit determines a plurality of schedules for distributing the load related to data processing to the plurality of storages based on past load conditions in the storage system, and distributes the load based on a schedule selected by a user from the plurality of schedules; The storage system according to claim 1 .

7. the storage system monitoring unit ends the load balancing in response to a notification of completion of the battery refresh from the storage control unit that made the battery refresh request. The storage system according to claim 1 .

8. the battery control unit issues the notification of the battery refresh request when the number of times the battery of the controller including the battery control unit has been charged reaches a predetermined number of times or more. The storage system according to claim 3 .

9. a plurality of storages each including a controller including a battery, a cache memory, a non-volatile area, and a storage control unit; a storage system monitoring unit that controls the plurality of storages, notifying, by the storage control unit, a battery refresh request for the battery in the controller including the storage control unit; the storage system monitoring unit responds to the battery refresh request from the storage control unit, distributing the load related to data processing to storages other than the storage that has requested the battery refresh; the storage control unit in the controller that has issued the battery refresh request discharges the battery of the controller that includes the storage control unit based on the amount of power required to save the data in the cache memory of the controller to the non-volatile area, and then causes the battery to be refreshed; A battery refresh method in a storage system.

10. a plurality of storages each including a controller including a battery, a cache memory, a non-volatile area, and a storage control unit; a storage system monitoring unit that controls the plurality of storages, notifying, by the storage control unit, a battery refresh request for the battery in the controller including the storage control unit; the storage system monitoring unit responds to the battery refresh request from the storage control unit, distributing the load related to data processing to storages other than the storage that has requested the battery refresh; the storage control unit in the controller that has issued the battery refresh request discharges the battery of the controller that includes the storage control unit based on the amount of power required to save the data in the cache memory of the controller to the non-volatile area, and then causes the battery to be refreshed; A program to make it happen.

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