STORAGE SYSTEM, METHOD AND PROGRAM FOR REFRESHING BATTERY IN STORAGE SYSTEM

Abstract

A storage system capable of performing battery refresh while maintaining high data integrity is provided. A storage control unit notifies a battery refresh request for a battery in a controller including the storage control unit. A 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 (114) discharges the battery based on the amount of power required to save data in the cache memory to a non-volatile area, and then causes the battery to be refreshed.

Description

[Technical field]

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

[0002] With the development of information technology, the amount of information handled has increased dramatically. Accordingly, the need for large-capacity, high-density storage systems has increased. The handling of data in this storage system is generally managed by a file system. When writing data, it is necessary to write it to a disk drive, but when performing temporary processing to ensure performance, cache memory provided in the storage including the disk drive is used. When using cache memory, if the power supply is interrupted, the data in the cache memory may be lost. Therefore, it is common to prevent data loss by installing a battery and saving it to non-volatile memory. In addition, since storage systems need to keep the data in the cache memory always in a state where they continue to operate 24 hours a day, 365 days a year depending on the usage environment, the battery capacity is maintained at a high level.

[0003] However, in devices that use batteries as a power source, the memory effect caused by repeated shallow charging and discharging causes a phenomenon in which the battery's operating time decreases. Therefore, in order to prevent the decrease in battery capacity caused by the memory effect, it is desirable to recover normal battery operation by discharging excess charges accumulated inside the battery, a process generally called battery refresh.

[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 the 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, when a power interruption occurs during battery refresh in a storage device included in a storage system, there is no data to be retained, or data to the storage device during battery refresh must be stopped, or data retention must be reduced to carry out the refresh at the risk of data loss.

[0007] In addition, a battery needs to be completely discharged in order to refresh it. Therefore, in storage devices that use large-capacity batteries, the battery capacity is maintained at a high level, so it takes time to discharge. Therefore, in devices such as storage systems that are required to be constantly running, it is difficult to perform battery refresh from the perspective of preventing data loss.

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

[0009] A storage system according to one embodiment 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, and 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 for which the battery refresh request has been made, 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 a battery refresh of the battery.

[0010] A battery refresh method in a storage system according to one embodiment of the present disclosure is applied to a storage system including a plurality of storages, each including 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 of the storage control unit and distributes the load related to data processing to storages other than the storage for which the battery refresh request has been made, 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 a battery refresh of the battery to be performed.

[0011] A program according to one aspect of the present disclosure causes a computer for a storage system comprising a plurality of storages, each comprising 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, distributing the load related to data processing to storages other than the storage for which the battery refresh request has been made; 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. Effect of the Invention

[0012] According to the above aspect, in the storage system, battery refresh can be performed in a state in which data integrity is high. [Brief description of the drawings]

[0013] [Figure 1] 1 is a block diagram showing a configuration of a storage system according to an embodiment of the present disclosure. [Diagram 2] FIG. 11 illustrates an operation of the storage system during battery refresh. [Diagram 3] FIG. 11 illustrates an operation of the storage system during battery refresh. [Figure 4] FIG. 1 is a diagram illustrating an example of a configuration of a storage system according to an embodiment of the present disclosure. [Diagram 5] 2 is a block diagram showing an example of a hardware configuration of a storage control unit, a battery control unit, and a storage system monitoring unit in the storage system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, each embodiment will be described with reference to the drawings. In all the drawings, the same or corresponding components are denoted 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) having 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 controllers (111, 121...), providing a redundant configuration. Each controller (111, 121...) is equipped with a battery (113, 123...), cache memory (115, 125...), and non-volatile area (116, 126...), which are paired together to ensure data integrity. Furthermore, each controller (111, 121...) is provided with a battery control unit (112, 122...) and 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;...) in order to prevent data loss in the event that 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 unit (112, 122;...) monitors the power capacity of the battery (113, 123;...) and controls charging and discharging of the battery (113, 123;...). The storage control unit (114, 124;...) manages the timing of battery refresh for the battery (113, 123;...) in the controller (111, 121;...) including the storage control unit (114, 124;...), and causes the battery refresh to be performed. Furthermore, the storage control unit (114, 124;...) also performs processing to hold data in the cache memory (115, 125;...) and to save data in the cache memory (115, 125;...) to the non-volatile area (116, 126;...) using power supply from the battery (113, 123;...) in the event of a power supply interruption.

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

[0020] Although the storage system (100) shown in FIG. 1 includes three storages (110, 130, 131) as an example, the present invention 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 a controller (111) in a storage (110) constituting the storage system (100) becomes necessary. Therefore, the operation relating 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 manner.

[0022] As shown in FIG. 2, in the storage (110), the battery control unit (112) in the controller (111) acquires the remaining charge of the internal battery (113) at predetermined intervals (S1-1) and determines whether the battery is in a charging state (S1-2). If the battery is not being charged (S1-2: No), the battery control unit (112) proceeds to process (S1-1) for the next remaining battery charge check. On the other hand, if the battery is being charged (S1-2: Yes), the battery control unit (112) checks the number of times the battery has been charged (S1-3). If the number of times the battery has been charged does not exceed a predetermined number (S1-4: No), the battery control unit (112) proceeds to process (S1-1) for the next remaining battery charge check. On the other hand, if the number of times the battery has been charged exceeds the predetermined number (S1-4: Yes), the battery control unit (112) determines that battery refresh is necessary and sets a battery refresh request flag (S1-5).

[0023] The storage control unit (114) checks at a predetermined interval whether the battery refresh request flag is set (S2-1). If the flag is not set (S2-1: No), the storage control unit (114) moves the process to (S2-1) for the next flag check. 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 the battery refresh request together with information identifying the controller that made the battery refresh request (S2-2).

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

[0025] The storage system monitoring unit (140) distributes the load from the storage (110) that performs the battery refresh to the other storages (130 / 131) (S3-2). In this way, the storage system monitoring unit (140) suppresses the amount of data in the cache memory (115) that should be saved when the power supply is interrupted in the storage (110) that performs the battery refresh. Note that reducing the load on the storage that performs the battery refresh means that the storage that does not perform the battery refresh will bear the load that the storage that performs the battery refresh should bear. For this reason, the storage system monitoring unit (140) has a log related to the load of the entire storage system (100) and plans a battery refresh schedule for a time period in which the load on the other storages is not too high even if the load on some storages is reduced by the battery refresh, based on past performance, particularly recent performance. In addition, when planning the battery refresh schedule, the storage system monitoring unit (140) plans it to be performed by one controller per storage in order to ensure data maintenance as a system when the power supply is interrupted during the battery refresh. In other words, when battery refresh requests come from both controllers in the same storage, the storage system monitoring unit (140) plans to perform battery refresh not simultaneously but to operate one controller's battery refresh after the other controller's battery refresh is completed.

[0026] As described above, by distributing the load from the storage (110) performing the battery refresh to the other storages (130 / 131), data in the cache memory (115) of the storage (110) performing the battery refresh is suppressed. If there is less data 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 the 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 the 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 charge required to save the data in the non-volatile area (116) according to the amount of data (S2-3). Here, the "required remaining battery charge" 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 non-volatile area (116) when the power supply is interrupted. The storage control unit (114) notifies the battery control unit (112) of the calculated remaining battery charge (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 a predetermined cycle, and when the amount of data falls below a predetermined amount or the required remaining battery level falls below a predetermined value, notify the battery control unit (112) of the calculated remaining battery level (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 level 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 battery refresh of the battery 113 (S1-9). After the complete discharge of the battery refresh is completed, 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), and 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 notifying the completion (S2-7).

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

[0034] If the power supply is interrupted during battery refresh, when battery refresh is being performed on the redundant controller side in the storage during battery refresh, for example, the controller (111), a state is maintained in which the data in the cache memory (125) can be saved in the non-volatile area (126) using the battery (123) mounted on the controller (121) side. In this case, the redundancy of the storage (110) alone decreases, but data retention 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. A plurality of recommended battery refresh schedule patterns are presented to a user based on past, particularly 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 determine a battery refresh schedule, and enables battery refresh to be performed according to a schedule that takes into account the load conditions of the storage system (100) expected to be realized in the future, as understood by the user.

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

[0040] In the present disclosure, the operation of the embodiment has been described in which the time required for battery refresh is shortened 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, when multiple cache memories are mounted in the controller, the storage control unit in the controller may reduce the power consumption of the entire storage by stopping the power supply to a part of the cache memory, for example, a cache memory that no longer stores data, when the suppression of data in the cache memory is suppressed to a certain amount or more, and perform battery refresh.

[0041] As described above, the storage system (100) of the present disclosure can enable non-stop battery refresh in a storage system that operates 24 hours a day, 365 days a year.

[0042] 4 is a diagram showing an example of the configuration of a storage system (100) according to an embodiment of the present disclosure. The storage system (100) includes a plurality of storages (110, 130, ...), each of which includes 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 monitoring unit (140) that controls the plurality of storages (110, 130). The storage control unit (114) notifies a battery refresh request for the battery (113) in the controller (111) including the storage control unit (114). The storage system monitoring unit (140) responds to the battery refresh request from the storage control unit (114) and distributes the load related to data processing to the storages (130, ...) other than the storage (110) that has the battery refresh request. The 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 the 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), the battery control unit (112), and the storage system monitoring unit (140) in the storage system (100). The hardware configuration of the storage control unit (114), the battery control unit (112), and the storage system monitoring unit (140) includes a CPU (11), a RAM (Random Access Memory) (12), a ROM (Read Only Memory) (13), and a recording device (14). The ROM (13) and the recording device (14) record programs and information that realize the functions of the storage control unit (114), the battery control unit (112), and the storage system monitoring unit (140). The RAM (12) is used as a working area for temporarily storing data and the like used by the CPU (11) and the like 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 other devices, such as a cache memory (115) or a non-volatile area (116) in the storage control unit (114). The input / output port (15) may be an input / output port for connecting an input / output device such as a keyboard, a mouse, or a display device in the storage system monitoring unit (140). The ROM (13) may be an EEPROM (Electrically Erasable Programmable Read-Only Memory) or the like, and the recording device (14) may be a hard disk, an 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 and have 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-mentioned embodiments. Various modifications that can be understood by a person 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 appropriately combined with other embodiments.

[0045] A part or all of the above-described embodiments may be described as, but is 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 a load related to data processing to storages other than the storage that has requested the battery refresh; the storage control unit in the controller which has issued the battery refresh request discharges the battery of the controller including 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 a battery refresh of the battery; 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 multiple controllers in the same storage, the storage system monitoring unit schedules battery refresh so that the multiple 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 in the non-volatile area in accordance with a 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 calculated; the battery control unit controls the battery to be discharged 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. A storage system according to any one of claims 1 to 3.

[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. A storage system according to any one of claims 1 to 4.

[0051] (Appendix 6) the storage system monitoring unit determines a plurality of schedules for distributing the load relating to data processing to the plurality of storages based on a past load state in the storage system, and distributes the load based on a schedule selected by a user from the plurality of schedules; 6. A storage system according to any one of claims 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 has made the battery refresh request. 7. A storage system according to any one of claims 1 to 6.

[0053] (Appendix 8) the battery control unit issues a 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 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; Responding to the battery refresh request from the storage control unit by the storage system monitoring unit, a load related to data processing is distributed to storages other than the storage that has requested the battery refresh; discharging the battery of the controller including 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 by the storage control unit in the controller that has issued the battery refresh request, and then performing a battery refresh of the battery; A method for refreshing a battery 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 the multiple controllers in the same storage, the storage system monitoring unit schedules battery refresh so that the multiple 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 has notified the battery refresh request calculates an amount of power required to save data in the non-volatile area in accordance with a 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 calculated; performing control by the battery control unit so that the battery is discharged up to the notified amount of power, and then performing 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 reaches or 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 appendixes 11 to 13.

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

[0059] (Appendix 16) determining a plurality of schedules for distributing the load relating to data processing to the plurality of storages based on the past load status of the storage system by the storage system monitoring unit, and distributing 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 appendixes 11 to 15.

[0060] (Appendix 17) 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 which has requested the battery refresh. A battery refresh method in a storage system according to any one of appendixes 11 to 16.

[0061] (Appendix 18) when the number of times that the battery of the controller including the battery control unit is charged reaches or exceeds a predetermined number of times, the battery control unit issues a notification of a 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; Responding to the battery refresh request from the storage control unit by the storage system monitoring unit, a load related to data processing is distributed to storages other than the storage that has requested the battery refresh; discharging the battery of the controller including 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 by the storage control unit in the controller that has issued the battery refresh request, and then performing a battery refresh of the battery; 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 the multiple controllers in the same storage, the storage system monitoring unit schedules battery refresh so that the multiple controllers in the same storage that have made battery refresh requests do not simultaneously perform battery refresh; The program according to 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 has notified the battery refresh request calculates an amount of power required to save data in the non-volatile area in accordance with a 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; performing control by the battery control unit so that the battery is discharged up to the notified amount of power, and then performing a battery refresh on the battery; 23. The program according to claim 21 or 22, further comprising:

[0065] (Appendix 24) when the load reaches or 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; and performing control by the storage control unit which has issued the battery refresh request to stop power supply to a cache memory which does not store the data during the battery refresh process. The program according to any one of appendices 21 to 24, further comprising:

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

[0068] (Appendix 27) 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 which has requested the battery refresh. 27. The program according to any one of appendices 21 to 26, further comprising:

[0069] (Appendix 28) when the number of times that the battery of the controller including the battery control unit is charged reaches or exceeds a predetermined number of times, the battery control unit issues a notification of a battery refresh request. The program according to 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 a load related to data processing to storages other than the storage that has requested the battery refresh; the storage control unit in the controller which has issued the battery refresh request discharges the battery of the controller including 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 a battery refresh of the battery. 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 multiple controllers in the same storage, the storage system monitoring unit schedules battery refresh so that the multiple 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 in the non-volatile area in accordance with a 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 calculated; the battery control unit controls the battery to be discharged 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 relating to data processing to the plurality of storages based on a past load state 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 has made the battery refresh request. The storage system according to claim 1 .

8. the battery control unit issues a 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 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; Responding to the battery refresh request from the storage control unit by the storage system monitoring unit, a load related to data processing is distributed to storages other than the storage that has requested the battery refresh; discharging the battery of the controller including 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 by the storage control unit in the controller that has issued the battery refresh request, and then performing a battery refresh of the battery; A method for refreshing a battery 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; Responding to the battery refresh request from the storage control unit by the storage system monitoring unit, a load related to data processing is distributed to storages other than the storage that has requested the battery refresh; discharging the battery of the controller including 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 by the storage control unit in the controller that has issued the battery refresh request, and then performing a battery refresh of the battery; A program to make it happen.

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