JP6981019B2 - Storage device, storage system, storage device control method, program - Google Patents

Description

The present invention relates to a storage device, a storage system, a control method of the storage device, and a program. In particular, the present invention relates to a storage device having a tier LD, a storage system, a control method of the storage device, and a program.

There is a storage device including an HDD (hard disk drive) and an SSD (solid state drive). In the storage device having an HDD, a WB (Write Back) method is adopted in which the head seek time is reduced by duplicating the unwritten cache and the writing to the HDD area is speeded up. On the other hand, in a storage device having an SSD, a WT (Write Through) method that omits cache duplication is adopted in order to utilize the high-speed performance and redundant structure (RAID: Redundant Arrays of Inexpensive Disks) of the SSD area.

There is also a technique for managing an LD (logical disk) that is a virtual combination of HDDs and SSDs as a hierarchical LD (see Patent Document 1). In such a storage device, either the WB method or the WT method is adopted.

Japanese Unexamined Patent Publication No. 2016-181197

The following analysis was made from the point of view of the present invention. The disclosure of the above prior art document shall be incorporated into this document by citation.

The storage device disclosed in Patent Document 1 has a problem that the write performance of the layered LD as a whole is deteriorated.

That is, when the WB method is adopted, the cache is duplicated even when writing to the SSD area, so that unnecessary processing is performed. On the other hand, when the WT method is adopted, writing to the HDD area causes a delay in processing of the storage device as a whole.

Therefore, an object of the present invention is to provide a storage device, a storage system, a control method of the storage device, and a program having improved write performance to the entire layer LD.

According to the first aspect of the present invention, a main cache memory for storing write data received from a host terminal and a main cache memory.
A sub-cache memory for storing duplicate data of the write data, and
A determination unit for determining whether the write destination of the write data stored in the main cache memory is a low-speed area or a high-speed area in the logical disk, and a determination unit.
When the determination unit determines that the writing is to the low speed area, the duplication unit that duplicates the write data stored in the main cache memory and stores it in the sub cache memory, and the duplication unit.
A write processing unit that writes write data stored in the main cache memory and duplicate data stored in the sub cache memory to the logical disk, and a write processing unit.
A storage device having the above is provided.

According to the second aspect of the present invention, a physical disk for storing data, a main cache memory for storing write data received from a host terminal, and a main cache memory.
A sub-cache memory for storing duplicate data of the write data, and
A determination unit for determining whether the write destination of the write data stored in the main cache memory is a low-speed area or a high-speed area in the logical disk, and a determination unit.
When the determination unit determines that the writing is to the low speed area, the duplication unit that duplicates the write data stored in the main cache memory and stores it in the sub cache memory, and the duplication unit.
A storage device having a write processing unit for writing write data stored in the main cache memory and duplicate data stored in the sub cache memory to the physical disk corresponding to each area of the logical disk.
A storage system including is provided.

According to the third viewpoint of the present invention, a determination step for determining whether the write destination of the write data stored in the main cache memory is a low-speed area or a high-speed area in the logical disk, and a determination step.
When it is determined by the determination step that the data is written to the low-speed area, the copy data stored in the main cache memory is duplicated and the duplicate data of the write data is stored in the sub-cache memory. ,
A write step of writing the write data stored in the main cache memory and the duplicate data stored in the sub cache memory to the physical disk corresponding to each area of the logical disk, and a write step.
A method of controlling a storage device including is provided.

According to the fourth aspect of the present invention, a determination process for determining whether the write destination of the write data stored in the main cache memory is a low-speed area or a high-speed area in the logical disk, and
When it is determined by the determination process that the data is written to the low-speed area, the write data stored in the main cache memory is duplicated and the duplicate data of the write data is stored in the sub-cache memory. ,
A write process for writing write data stored in the main cache memory and duplicate data stored in the sub cache memory to a physical disk corresponding to each area of the logical disk, and a write process.
Is provided with a program that causes the computer to execute.

According to each viewpoint of the present invention, there are provided a storage device, a storage system, a control method of the storage device, and a program in which the write performance of the entire layer LD is improved.

It is a figure for demonstrating the outline of one Embodiment. It is a block diagram which shows one configuration of the storage apparatus of 1st Embodiment. It is a block diagram which shows one configuration of a controller 110. It is a figure which showed an example of the information stored in the management table 116. It is a figure which shows the processing flow of the entire storage device 10. It is a figure which shows the processing sequence by each controller 110. It is a figure which shows the modification of the host control unit 100. It is a figure which shows the modification of the host control unit 100.

Preferred embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the drawing reference reference numerals added to the following description are added to each element for convenience as an example for assisting understanding, and the present invention is not intended to be limited to the illustrated embodiment. Further, the connection line between the blocks in each drawing includes both bidirectional and unidirectional, and is shown or deleted as appropriate for the purpose of clarifying the drawing. In addition, drawing reference codes are also added or deleted as appropriate for clarification.

As shown in FIG. 1, the storage device 10 has a host control unit 100, and the host control unit 100 has a plurality of controllers 110 and a logical disk 120. Each controller 110 has the same structure that functions as a main controller or a sub controller, and each has a cache memory 115, a determination unit 117, a duplication unit 118, and a write processing unit 119. The logical disk 120 includes a layered LD (logical disk) having an HDD (hard disk drive) area and an SSD (solid state drive) area. The HDD area is also referred to as a low-speed area, and the SSD area is also referred to as a high-speed area. Each controller 110 is connected to each other and is also connected to a host terminal (not shown) and a logical disk 120.

The cache memory 115 stores the write data received from the host terminal or the duplicate data of the write data. The determination unit 117 determines whether the write data stored in the main cache memory is a write to the HDD area or a write to the SSD area. When the determination unit 117 determines that the writing is to the HDD area, the duplication unit 118 duplicates the write data and stores it in the sub-cache memory. The write processing unit 119 writes the write data stored in the main cache memory and the duplicate data stored in the sub cache memory to the physical disk (that is, HDD or SSD) corresponding to the logical disk 120.

To give a specific example, when the storage device 10 receives the write data from the host terminal, the write data is input to one of the controllers 110 and stored in the cache memory 115. Here, the controller 110 to which the write data is input functions as the main controller, and the controller 110 to which the write data is not input functions as the sub controller. Hereinafter, a case where the controller 110 (# 0) functions as the main controller and the controller 110 (# 1) functions as the sub controller will be described.

The determination unit 117 of the controller 110 (# 0) determines whether the write destination of the write data stored in the main cache memory (that is, the cache memory 115 of the controller 110 (# 0)) is the HDD area or the SSD area. judge. When the determination unit 117 of the controller 110 (# 0) determines that the writing is to the HDD area, the determination unit 117 duplicates the write data stored in the main cache memory and duplicates the write data of the sub cache memory (controller 110 (# 1)). It is stored in the cache memory 115). The write processing unit 119 of the controller 110 (# 0) writes the write data stored in the main cache memory to the HDD or SSD. Further, the write processing unit 119 of the controller 110 (# 1) writes the duplicated data stored in the sub-cache memory to the HDD.

As described above, the storage device 10 executes the writing to the HDD area by the WB (Write Back) method of duplicating the cache as shown by the data flow indicated by the solid line arrow and the broken line arrow in FIG. On the other hand, the storage device 10 performs writing to the SSD area by a WT (Write Through) method that omits the data flow indicated by the broken line arrow in FIG. 1, that is, omits the duplication of the cache. Therefore, in the storage device 10 described above, the write performance to the entire layer LD is improved.

[First Embodiment]
As shown in FIG. 2, the storage device 10 is connected to the host terminal 30 and has a host control unit 100 and a physical disk group 200. The physical disk group 200 has a plurality of physical disks 210 including HDDs and SSDs, and each physical disk 210 is connected to the storage device 10 via a bus or the like. The physical disk 210 can also be arranged outside the storage device 10. The host terminal 30 is a computer or the like connected via a network, and transmits write data or the like to the storage device 10.

The host control unit 100 has a plurality of controllers 110 having the same structure and a logical disk 120. The logical disk 120 includes an HDD (hard disk drive) area corresponding to a physical address in the HDD and an SSD (solid state drive) area corresponding to the physical address in the SSD. The HDD area and the SSD area are virtually integrated as one layered LD (logical disk), and the logical address of the layered LD is recognized as a write destination address by the host terminal 30.

Each controller 110 is made redundant so that the writing process of the storage device 10 as a whole can be continued even if any of the controllers 110 fails. When executing the writing process to the HDD area, one controller 110 functions as a main controller, and the other controller 110 functions as a sub controller.

Specifically, as shown in FIG. 3, each controller 110 has a host I / F (interface) 111, a disk I / F 112, a storage unit 113, and a control unit 114. The storage unit 113 has a cache memory 115 and a management table 116, and the control unit 114 has a determination unit 117, a duplication unit 118, and a write processing unit 119. Note that FIG. 3 is a block diagram showing the structure of the controller 110 (# 0) shown in FIG.

The host I / F 111 functions as an interface to the host terminal 30, and stores the write data received from the host terminal 30 in the cache memory 115. Specifically, the host I / F 111 is connected to the host terminal 30 by an external interface such as Fiber Chanel, Serial Attached SCSI (SAS), and Internet Small Computer System Interface (iSCS). Further, the host I / F 111 is connected to the control unit 114 by an internal bus such as PCI Express (Peripheral Component Interconnect Express).

The disk I / F 112 functions as an interface connected to the physical disk 210, and stores the data stored in the cache memory 115 in the physical disk 210 under the control of the control unit 114. Specifically, the disk I / F 112 functions as a module for converting the communication method between the external interface and the internal bus. The disk I / F 112 is connected to the physical disk 210 by an external interface such as SAS, InfiniBand, or PCI Express, and is connected to the control unit 114 by an internal bus such as PCI Express.

The cache memory 115 is a module for holding cache data, is composed of a DDR3 SDRAM (Double-Data-Rate 3 Synchronous Dynamic Random Access Memory), a DDR4 SDRAM, or the like, and is connected to a control unit 114. Specifically, the cache memory 115 stores the write data received from the host terminal 30 or the duplicate data of the write data. The write data and duplicate data stored in the cache memory 115 include information indicating the logical address of the write destination. In addition, the write data and the duplicate data include information for distinguishing from each other, for example, a flag.

The management table 116 stores information for determining the area (HDD area or SSD area) of the logical disk 120 of the write destination from the logical address of the write destination received from the host terminal 30 together with the write data. As shown in FIG. 4, the management table 116 stores logical addresses and physical addresses in association with each other, and each physical address is either an HDD area or an SSD area. Information indicating whether or not is added. The information stored in the management table 116 is appropriately updated when the configuration of the logical disk 120 is changed.

The determination unit 117 determines whether the data stored in the cache memory 115 is a write to the HDD area or a write to the SSD area. Specifically, the determination unit 117 monitors the cache memory 115 and detects that data is stored in the cache memory 115. When the determination unit 117 detects that the data is stored, the determination unit 117 refers to the flag attached to the data stored in the cache memory 115, and either the write data received from the host terminal 30 or the duplicated data obtained by duplicating the write data. Determine if there is. When it is determined that the data is duplicated, the determination unit 117 instructs the write processing unit 119 to write the duplicated data stored in the cache memory 115 to the physical disk 210.

On the other hand, when it is determined that the data is write data, the determination unit 117 further determines whether the data stored in the cache memory 115 is write to the HDD area or write to the SSD area. Specifically, the determination unit 117 refers to the management table 116 and determines whether the write destination logical address assigned to the write data is the HDD area or the SSD area. When it is determined that the logical address of the writing destination is the SSD area, the determination unit 117 instructs the write processing unit 119 to write the write data stored in the cache memory 115 to the physical disk 210.

On the other hand, when it is determined that the logical address of the writing destination is the HDD area, the determination unit 117 instructs the duplication unit 118 to duplicate the write data stored in the cache memory 115.

The duplication unit 118 duplicates the write data stored in the cache memory 115, and stores the duplication data in the cache memory 115 of the other controller 110. For example, the duplication unit 118 of the controller 110 (# 0) duplicates the write data stored in the cache memory 115 of the controller 110 (# 0) and stores the duplication data in the cache memory 115 of the controller 110 (# 1). .. In this case, the cache memory 115 of the controller 110 (# 0) corresponds to the main cache memory, and the cache memory 115 of the controller 110 (# 1) corresponds to the sub cache memory. Then, the duplication unit 118 instructs the write processing unit 119 to write the write data stored in the cache memory 115 of the controller 110 (# 0) to the physical disk 210.

The write processing unit 119 writes the write data and the duplicate data stored in the cache memory 115 to the physical disk 210, and deletes the data stored in the cache memory 115. Specifically, when the write processing unit 119 receives a write instruction for duplicate data from the determination unit 117, the write processing unit 119 communicates with the write processing unit 119 of the controller 110 (# 1) to assign processing. Then, the write processing unit 119 writes the assigned data to the physical disk 210. In this case, the controller 110 (# 0) functions as a sub-controller. That is, the write processing unit 119 (# 0) of the controller 110 (# 0) functions as a sub write processing unit that writes the duplicated data stored in the sub cache memory to the HDD.

When the write processing unit 119 receives a write data write instruction from the determination unit 117, the write processing unit 119 independently receives the write data stored in the cache memory 115 without communicating with the write processing unit 119 of the controller 110 (# 1). Write to physical disk 210. In this case, the controller 110 (# 0) functions as the main controller. That is, the write processing unit 119 of the controller 110 (# 0) functions as a main write processing unit that independently writes the write data stored in the main cache memory to the SSD.

Further, when the write processing unit 119 receives a write data write instruction from the duplication unit 118, the write processing unit 119 communicates with the write processing unit 119 of the controller 110 (# 1) to allocate processing and physically assigns the assigned data. Write to disk 210. In this case, the controller 110 (# 0) functions as the main controller. That is, the write processing unit 119 of the controller 110 (# 0) functions as a main write processing unit that writes the write data stored in the main cache memory to the HDD.

Hereinafter, a series of processing flows by the storage device 10 and processing by each functional unit will be described with reference to the drawings.

FIG. 5 is a diagram showing a processing flow of the entire storage device 10. When the write data is received from the host terminal 30 (step S11), the host control unit 100 executes the write data determination process (step S12). If the write data is written to the HDD area (step S13, YES), the host control unit 100 writes the write data to the HDD while duplicating it (step S14). On the other hand, if the write data is written to the SSD area (step S13, NO), the host control unit 100 writes the write data to the SSD without duplicating it (step S15).

FIG. 6 is a diagram showing a processing sequence performed by each controller 110 from the reception of write data (step S11) to the writing to the physical disk 210 (step S14 or step S15). Note that FIG. 6 describes a case where the controller 110 (# 0) functions as the main controller and the controller 110 (# 1) functions as the sub controller.

As shown in FIG. 6, when the write data received from the host terminal is stored in the cache memory 115 (step S21), the determination unit 117 (# 0) determines whether the write data is the write data or the duplicate data. (Step S22). Here, the determination unit 117 (# 0) naturally determines that the data is written data.

Next, the determination unit 117 (# 0) further determines whether the data stored in the cache memory 115 is a write to the HDD area or a write to the SSD area (step S23). When it is determined that the writing is to the SSD area (step S23, NO), the writing processing unit 119 writes the writing data stored in the cache memory 115 to the SSD independently (step S24).

On the other hand, when it is determined that the data is written to the HDD area (step S23, YES), the duplication unit 118 duplicates the write data stored in the cache memory 115 and puts it in the cache memory 115 (# 1). The duplicated data is stored (step S25). Subsequently, the write processing unit 119 (# 0) performs communication for processing assignment with the write processing unit 119 (# 1) of the controller 110 (# 1) (step S26), and transfers the assigned data to the HDD. Write (step S27).

Returning to step S25, the determination unit 117 (# 1) of the controller 110 (# 1) determines whether the duplicate data is write data or duplicate data when the duplicate data is stored in the cache memory 115 (step S31). (Step S32). Here, the determination unit 117 (# 1) naturally determines that the data is written data. Subsequently, the write processing unit 119 (# 1) performs communication for processing allocation with the write processing unit 119 (# 0) of the controller 110 (# 0) (step S33), and transfers the assigned data to the HDD. Write (step S34).

It should be noted that the storage of the duplicated data (step S31) by the controller 110 (# 1) and the writing to the HDD can be performed at any timing. In that case, when the storage of the duplicated data is confirmed, the controller 110 (# 1) reports the completion of the write process to the host terminal 30 via the controller 110 (# 0).

As described above, in the storage device 10 of the first embodiment, the writing to the HDD area is executed by the WB method that duplicates the cache, and the writing to the SSD area is executed by the WT method that omits the duplication of the cache. , The write performance to the entire layer LD is improved. Further, when writing to the SSD area, the required area of the cache memory 115 is reduced.

In the first embodiment, the number and configuration of the host control unit 100, the controller 110, the logical disk 120, and the like can be arbitrarily changed. For example, the number of controllers 110 may be three or more.

Further, for example, as shown in FIG. 7, in the host control unit 100, the host I / F111, the disk I / F112, the management table 116, the determination unit 117, and the duplication unit 118 may be provided separately from each controller 110. In this case, the write data received from the host terminal 30 is input to the determination unit 117, and the determination unit 117 stores the write data to the SSD area in the cache memory 115 of any of the controllers 100. Further, regarding writing to the HDD area, the determination unit 117 instructs the duplication unit 118 to copy the write data. By doing so, each controller 110 only needs to have the cache memory 115 and the write processing unit 119, and the configuration of the controller 110 is simplified.

Further, as shown in FIG. 8, the main cache memory 115 and the sub cache memory 115 may be defined in advance.

The storage device 10 is realized by, for example, a computer equipped with a processing module. The processing module is realized, for example, by the CPU executing a program stored in the memory. In addition, the program can be downloaded via a network or updated using a storage medium in which the program is stored. Further, the processing module may be realized by a semiconductor chip. That is, the function performed by the processing module may be realized by some hardware and / or software.

Some or all of the above embodiments may also be described, but not limited to:

(Appendix 1)
The main cache memory that stores the write data received from the host terminal,
A sub-cache memory for storing duplicate data of the write data, and
A determination unit for determining whether the write destination of the write data stored in the main cache memory is a low-speed area or a high-speed area in the logical disk, and a determination unit.
When the determination unit determines that the writing is to the low speed area, the duplication unit that duplicates the write data stored in the main cache memory and stores it in the sub cache memory, and the duplication unit.
A write processing unit that writes write data stored in the main cache memory and duplicate data stored in the sub cache memory to a physical disk corresponding to each area of the logical disk, and a write processing unit.
Storage device with.

(Appendix 2)
It also has a management table that stores the logical address of the logical disk in association with the information indicating whether it is a low-speed area or a high-speed area.
The determination unit collates the write destination logical address assigned to the write data with the information stored in the management table, and the write destination of the write data is either a low-speed area or a high-speed area in the logical disk. The storage device according to Appendix 1 for determining whether or not there is a storage device.

(Appendix 3)
The logical disk is a hierarchical LD (logical disk) having an HDD (hard disk drive) area and an SSD (solid state drive) area, the HDD area corresponds to the low speed area, and the SSD area corresponds to the high speed area. The storage device according to Appendix 1 or 2.

(Appendix 4)
The write processing unit corresponds to the main write processing unit that writes the write data stored in the main cache memory to the physical disk corresponding to the low-speed area or the high-speed area, and the duplicate data stored in the sub-cache memory to the low-speed area. The storage device according to any one of Supplementary note 1 to 3, which has a sub write processing unit for writing to a physical disk.

(Appendix 5)
It has a plurality of controllers including the write processing unit and the cache memory, and has a plurality of controllers.
When one controller functions as the main controller and the other controller functions as the sub controller, the write processing unit of the main controller functions as the main write processing unit, and the cache memory of the main controller is the main cache memory. 4. The storage device according to Appendix 4, wherein the write processing unit of the sub controller functions as the sub write processing unit, and the cache memory of the sub controller functions as the sub cache memory.

(Appendix 6)
The storage device according to Appendix 5, wherein the controller further includes the determination unit and the duplication unit.

(Appendix 7)
A physical disk that stores data, a main cache memory that stores write data received from the host terminal, and
A sub-cache memory for storing duplicate data of the write data, and
A determination unit for determining whether the write destination of the write data stored in the main cache memory is a low-speed area or a high-speed area in the logical disk, and a determination unit.
When the determination unit determines that the writing is to the low speed area, the duplication unit that duplicates the write data stored in the main cache memory and stores it in the sub cache memory, and the duplication unit.
A storage device having a write processing unit for writing write data stored in the main cache memory and duplicate data stored in the sub cache memory to the physical disk corresponding to each area of the logical disk.
Storage system including.

(Appendix 8)
A determination step for determining whether the write destination of the write data stored in the main cache memory is a low-speed area or a high-speed area in the logical disk, and a determination step.
When it is determined by the determination step that the data is written to the low-speed area, the copy data stored in the main cache memory is duplicated and the duplicate data of the write data is stored in the sub-cache memory. ,
A write step of writing the write data stored in the main cache memory and the duplicate data stored in the sub cache memory to the physical disk corresponding to each area of the logical disk, and a write step.
How to control the storage device, including.

(Appendix 9)
Judgment processing for determining whether the write destination of the write data stored in the main cache memory is the low-speed area or the high-speed area in the logical disk, and
When it is determined by the determination process that the data is written to the low-speed area, the write data stored in the main cache memory is duplicated and the duplicate data of the write data is stored in the sub-cache memory. ,
A write process for writing write data stored in the main cache memory and duplicate data stored in the sub cache memory to a physical disk corresponding to each area of the logical disk, and a write process.
A program that causes a computer to run.

The disclosure of the above patent documents shall be incorporated into this document by citation. Within the framework of the entire disclosure (including the scope of claims) of the present invention, it is possible to change or adjust the embodiments or examples based on the basic technical idea thereof. Further, various combinations or selections of various disclosure elements (including each element of each claim, each element of each embodiment or embodiment, each element of each drawing, etc.) within the scope of the claims of the present invention. Is possible. That is, it goes without saying that the present invention includes all disclosure including claims, various modifications and modifications that can be made by those skilled in the art in accordance with the technical idea.

10 Storage device 30 Host terminal 100 Host control unit 110 Controller 111 Host I / F
112 Disc I / F
113 Storage unit 114 Control unit 115 Cache memory 116 Management table 117 Judgment unit 118 Duplicate unit 119 Write processing unit 120 Logical disk 200 Physical disk group 210 Physical disk

Claims (8)

The main cache memory that stores the write data received from the host terminal,
A sub-cache memory for storing duplicate data of the write data, and
A determination unit for determining whether the write destination of the write data stored in the main cache memory is a low-speed area or a high-speed area in the logical disk, and a determination unit.
When the determination unit determines that the writing is to the low speed area, the duplication unit that duplicates the write data stored in the main cache memory and stores it in the sub cache memory, and the duplication unit.
The main write processing unit that writes the write data saved in the main cache memory to the physical disk,
It has a sub write processing unit that writes duplicate data stored in the sub cache memory to a physical disk, and has.
Regarding the write data determined to be written to the high-speed area by the determination unit, the main write processing unit reads the data from the main cache memory and writes the data to the physical disk corresponding to the high-speed area.
Regarding the write data determined to be written to the low speed region by the determination unit, the main write processing unit and the sub write processing unit communicate for processing allocation, and the data assigned to each is used as described above. Write to the physical disk corresponding to the low speed area,
Storage device. It also has a management table that stores the logical address of the logical disk in association with the information indicating whether it is a low-speed area or a high-speed area.
The determination unit collates the write destination logical address assigned to the write data with the information stored in the management table, and the write destination of the write data is either a low-speed area or a high-speed area in the logical disk. The storage device according to claim 1, wherein it is determined whether or not there is a storage device. The logical disk is a hierarchical LD (logical disk) having an HDD (hard disk drive) area and an SSD (solid state drive) area, the HDD area corresponds to the low speed area, and the SSD area corresponds to the high speed area. The storage device according to claim 1 or 2. It has multiple controllers including a write processing unit and a cache memory.
When one controller functions as the main controller and the other controller functions as the sub controller, the write processing unit of the main controller functions as the main write processing unit, and the cache memory of the main controller is the main cache memory. The storage device according to any one of claims 1 to 3, wherein the write processing unit of the sub controller functions as the sub write processing unit, and the cache memory of the sub controller functions as the sub cache memory. .. The storage device according to claim 4, wherein all of the one controller functioning as the main controller and the other controllers functioning as the sub-controller further have the determination unit and the duplication unit. A physical disk that stores data, a main cache memory that stores write data received from the host terminal, and
A sub-cache memory for storing duplicate data of the write data, and
A determination unit for determining whether the write destination of the write data stored in the main cache memory is a low-speed area or a high-speed area in the logical disk, and a determination unit.
When the determination unit determines that the writing is to the low speed area, the duplication unit that duplicates the write data stored in the main cache memory and stores it in the sub cache memory, and the duplication unit.
The main write processing unit that writes the write data saved in the main cache memory to the physical disk,
A storage device including a sub write processing unit for writing duplicate data stored in the sub cache memory to a physical disk, and a storage device including the sub write processing unit.
Regarding the write data determined to be written to the high-speed area by the determination unit, the main write processing unit reads the data from the main cache memory and writes the data to the physical disk corresponding to the high-speed area.
Regarding the write data determined to be written to the low speed region by the determination unit, the main write processing unit and the sub write processing unit communicate for processing allocation, and the data assigned to each is used as described above. Write to the physical disk corresponding to the low speed area ,
Storage system. A determination step for determining whether the write destination of the write data stored in the main cache memory is a low-speed area or a high-speed area in the logical disk, and a determination step.
When it is determined by the determination step that the data is written to the low-speed area, the copy data stored in the main cache memory is duplicated and the duplicate data of the write data is stored in the sub-cache memory. ,
With respect to the write data determined to be written to the high-speed area by the determination step, the step of reading the data from the main cache memory and writing the data to the physical disk corresponding to the high-speed area,
Regarding the write data determined to be written to the low speed area by the determination step, the main write processing unit that reads the data from the main cache memory and writes the data to the physical disk corresponding to the low speed area, and the sub cache memory. A step of reading data and distributing it to a sub write processing unit that writes data to a physical disk corresponding to the low-speed area to execute data writing .
The data writing method that the storage device performs. Judgment processing for determining whether the write destination of the write data stored in the main cache memory is the low-speed area or the high-speed area in the logical disk, and
When it is determined by the determination process that the data is written to the low-speed area, the write data stored in the main cache memory is duplicated and the duplicate data of the write data is stored in the sub-cache memory. ,
With respect to the write data determined to be written to the high-speed area by the determination process, the process of reading the data from the main cache memory and writing it to the physical disk corresponding to the high-speed area.
Regarding the write data determined to be written to the low-speed area by the determination process, the main write processing unit that reads the data from the main cache memory and writes the data to the physical disk corresponding to the low-speed area, and the sub-cache memory. A process of reading data and distributing it to a sub write processing unit for writing to a physical disk corresponding to the low-speed area to execute data writing .
A program that causes a computer to run.

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