JP6015700B2 - Information storage device and information storage method - Google Patents

Description

  The present invention relates to an information storage device and an information storage method for improving read / write performance.

  As information storage devices, devices with improved read / write performance are known. This information storage device uses an SSD (Solid State Drive) that has excellent read / write performance but has a limited number of times of writing.

  An example of an information storage device is described in Patent Document 1. The information storage device described in Patent Literature 1 includes an SSD and an HDD (Hard Disk Drive) as storage units, and when the usage value of the SSD exceeds a threshold, the data transfer destination is changed to the HDD instead of the SSD. .

JP 2012-234458 A

  However, the technique described in Patent Document 1 described above only changes the data transfer destination to the HDD instead of the SSD, and the data read / write speed of the HDD is slower than that of the SSD. Therefore, the technique described in Patent Document 1 has a problem that performance degradation occurs when the transfer destination is an HDD. Further, since the technique described in Patent Document 1 writes data in either SSD or HDD, the data is not made redundant. In addition, when the SSD is replaced, the data in the SSD is not saved to another storage medium, so that there is a problem that data is lost.

  An object of the present invention is to provide an information storage device and an information storage method capable of solving the above-described problems.

  A first information storage device according to an embodiment of the present invention includes a plurality of SSDs (Solid State Drives), and each SSD is divided into two areas, a write data area and a read data area. A secondary cache unit, a buffer memory, a spare disk device as a storage medium, and two SSDs among the secondary cache SSDs form a redundant configuration, and the write data transfer destination is an area for the write data of both SSDs. In addition, when the number of writes of each SSD in the redundant configuration is monitored and an SSD in which the number of writes reaches the threshold is detected, the area for the write data of the other SSD is copied to the spare disk device, In addition, the write data transfer destination is set in the write data area of the other SSD and the buffer memory. And a controller for copying the data transferred to the buffer memory to the spare disk device.

  In the first information storage method according to an aspect of the present invention, the control unit forms a redundant configuration with two SSDs of the secondary cache SSDs, and the write data transfer destination is an area for the write data of both SSDs. The number of writes of each SSD in the redundant configuration is monitored, and when the SSD that has reached the threshold value is detected, the write data area of the other SSD is copied to the spare disk device, and the write data Is set in the other SSD write data area and the buffer memory, and the data transferred to the buffer memory is copied to the spare disk device.

  According to the present invention, it is possible to obtain an effect that the secondary cache can always be made redundant and stored without performance degradation.

FIG. 1 is a block diagram showing the configuration of the information storage device 1000 according to the first embodiment of the present invention. FIG. 2 is a diagram illustrating an example of the SSD write count management table according to the first embodiment. FIG. 3 is a diagram illustrating an example of the SSD threshold management table according to the first embodiment. FIG. 4 is a diagram illustrating an example of a copy management table according to the first embodiment. FIG. 5 is a flowchart illustrating an outline of an operation of controlling data writing to the secondary cache 140 of the control unit 110 in the information storage device 1000 according to the first embodiment. FIG. 6 is a flowchart illustrating an outline of control operation after data writing to the secondary cache 140 of the control unit 110 in the information storage device 1000 according to the first embodiment. FIG. 7 shows that the life flag in the SSD write count management table of the second SSD 142 in the information storage device 1000 in the first embodiment is “1”, that is, the write count of the second SSD 142 exceeds the threshold value. 6 is a flowchart showing an outline of an operation of controlling data writing to the secondary cache 140 of the control unit 110 in a case. FIG. 8 shows that the life flag in the SSD write count management table of the second SSD 142 in the information storage device 1000 according to the first embodiment is “1”, that is, the write count of the second SSD 142 has exceeded the threshold value. 7 is a flowchart showing an outline of control operation after data writing to the secondary cache 140 of the control unit 110 in the case. FIG. 9 is a block diagram illustrating a configuration of the information storage device 1000 after a new SSD is added to the secondary cache 140 in the information storage device 1000 according to the first embodiment of this invention. In FIG. 10, a third SSD 143 is added to the secondary cache 140 in the information storage device 1000 according to the first embodiment, and data is copied from the first SSD 141 to the third SSD 143 so that a redundant configuration is achieved. It is a flowchart which shows the outline | summary of the operation | movement to construct | assemble. FIG. 11 is a block diagram showing a configuration of the information storage device 1001 according to the second embodiment of the present invention.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram showing the configuration of the information storage device 1000 according to the first embodiment of the present invention. Referring to FIG. 1, the information storage device 1000 includes a communication unit 100, a control unit 110, a storage unit 120, a secondary cache 140, a data disk device 150, a buffer memory 160, and a spare disk device 170. The secondary cache 140 includes a first SSD 141 and a second SSD 142.

  Next, the configuration of the information storage device 1000 according to the first embodiment will be described.

  The communication unit 100 transmits / receives data to / from an external information processing apparatus (not shown).

  The control unit 110 monitors at least the number of writes of each SSD in the secondary cache 140, and when detecting an SSD that has reached the threshold value, the buffer memory 160 and the spare disk device 170 are used instead of the SSD. Is set as the data transfer destination. When the size of data to be written to the secondary cache 140 is larger than the free area of the secondary cache 140, the control unit 110 writes the data to the data disk device 150 instead of the secondary cache 140.

  If the specific condition is satisfied, the control unit 110 copies the data in the secondary cache 140 to the data disk device 150 and erases the data in the secondary cache 140, but this is omitted in the description of the operation of this embodiment. To do. The specific condition is, for example, a case where the capacity of a primary cache unit (not shown) has a free area of a certain level or more and the busy rate of the data disk device 150 is a certain value or less.

  The storage unit 120 stores the SSD write count, threshold, and data transfer information in the secondary cache 140 as an SSD write count management table, an SSD threshold management table, and a copy management table, respectively.

  FIG. 2 shows an example of the SSD write count management table. The SSD write count management table includes an ID for identifying an SSD, a redundant configuration number indicating which SSD and which SSD have a redundant configuration, the write count of each SSD, and each SSD reaching a threshold described later. It consists of a life flag indicating whether or not

  FIG. 3 shows an example of the SSD threshold management table. The SSD threshold value management table includes threshold values representing the number of times of writing determined as the life of each SSD.

  FIG. 4 shows an example of the copy management table. The copy management table includes copy source information indicating the copy source drive information and data address, copy destination drive information and copy destination information indicating the data address, and a buffer for temporarily storing data when copying the contents of the disc. It consists of memory drive information and buffer memory information indicating data addresses. The correspondence between the copy source information and the copy destination information, or the copy source information and the buffer memory information is the correspondence information of the data having a redundant configuration at the time of SSD replacement.

  The secondary cache 140 is a storage medium having a higher data processing speed than the data disk device 150 and the spare disk device 170. In addition, the secondary cache 140 in the first embodiment of the present invention is configured by a plurality of SSDs. Further, the secondary cache 140 in the present embodiment is configured by a first SSD 141 and a second SSD 142. Each SSD further includes an area for write data that is write data to the information storage device 1000 received by the communication unit 100 from an external device (not shown), and an area for read data that is read data from the data disk device 150. It is divided into two. That is, the first SSD 141 has two areas, an area 1411 for Write data and an area 1412 for Read data. Similarly, the second SSD 142 has two areas, an area 1421 for Write data and an area 1422 for Read data. The ratio between the write data area and the read data area is appropriately set by the administrator.

  The data disk device 150 is a storage medium for storing data that cannot be stored in the primary cache and the secondary cache 140 (not shown) of the information storage device 1000 due to insufficient capacity. The data disk device 150 in the present embodiment is configured by an HDD (Hard Disk Drive). The data disk device 150 may be configured with a single storage medium or a redundant configuration with a plurality of storage media.

  The buffer memory 160 is a recording medium whose data processing speed is at least higher than that of the data disk device 150.

  The spare disk device 170 is a storage medium originally provided in the information storage device 1000 as an alternative disk when the data disk device 150 fails. In the present invention, the control unit 110 is used as a storage medium to which data is transferred together with the buffer memory 160 as a secondary cache instead of SSD. The spare disk device 170 in this embodiment is configured by an HDD. The spare disk device 170 may have a plurality of HDDs, and may be selected according to specific conditions each time an SSD is replaced. For example, the spare disk device 170 may be selected to use an HDD with the largest free capacity.

The CPU is included in the control unit 110, and a control program is stored in the storage unit 120 or other non-illustrated non-volatile memory, and is read and executed by the CPU.

  The operation of the information storage device 1000 configured as described above will be described with reference to the flowcharts of FIGS. 5, 6, 7, 8, and 10, and the block diagram of FIG.

  FIG. 5 and FIG. 6 are flowcharts showing an overview of data write control operations to the secondary cache 140 of the control unit 110 in the information storage device 1000 according to the first embodiment. Note that the processing according to this flowchart may be executed based on the above-described program control by the CPU. Note that both of the life flags in the SSD write count management table of the first SSD 141 and the second SSD 142 are “0”. That is, it is assumed that the write count has not reached the threshold value for either SSD.

  As shown in FIG. 5, when the control unit 110 writes data to the secondary cache 140, the control unit 110 first checks whether the data to be written is write data (step S101). If the data to be written is Read data (NO in step S101), the control unit 110 controls to write the data read from the data disk device 150 only in one of the areas 1412 and 1422, which has a large free area. (Step S102). If the data to be written is write data (YES in step S101), the control unit 110 further checks whether the size of the data to be written is smaller than the free capacity of each of the SSD 141 and SSD 142 (step S103). When the size of the data to be written is larger than the free capacity of each of the SSD 141 and SSD 142 (NO in step S103), the control unit 110 writes to the data disk device 150 instead of each SSD of the secondary cache 140 (step S104). ), As shown in FIG. 6, the control unit 110 ends the process of this operation. When the size of the data to be written is smaller than the free space of each of the SSD 141 and SSD 142 (YES in step S103), the control unit 110 controls to write the same data in both the area 1411 and the area 1421 (step S105).

  Next, the control unit 110 updates the number of times of writing of the written SSD in the SSD writing number management table stored in the storage unit 120 (step S106).

  As shown in FIG. 6, the control unit 110 then compares the threshold value in the SSD threshold value management table stored in the storage unit 120 with the write count of each SSD in the SSD write count management table, It is investigated whether there is any SSD whose write count exceeds the threshold (step S107). If not (NO in step S107), the control unit 110 ends the process of this operation. If there is (YES in step S107, the SSD whose number of writes has exceeded the threshold value thereafter is the second SSD 142), the control unit 110 sets the life flag of the SSD 142 in the SSD write number management table to “0”. Is changed to “1” (step S108).

  Next, the control unit 110 adds the SSD 141 whose life flag is “0” to the copy source information to the drive information in the copy management table stored in the storage unit 120, and the spare disk device 170 as the copy destination information. Is added (step S109).

  Next, the control unit 110 copies all the data stored in the area 1411 of the SSD 141 to the spare disk device 170 (step S110).

Next, the control unit 110 describes the data address of the copied SSD 141 in the data address of the copy source information in the copy management table stored in the storage unit 120, and copies the spare disk to the data address of the copy destination information. The data address of the device 170 is described (step S111).
This completes the data write control to the secondary cache 140 of the control unit 110 in the information storage device 1000 and the operation of the SSD processing in which the write count exceeds the threshold.

  7 and 8 show that the life flag in the SSD write count management table of the second SSD 142 is “1” in the information storage device 1000 according to the first embodiment, that is, the write count of the second SSD 142 is the threshold. 6 is a flowchart showing an outline of an operation of controlling data writing to the secondary cache 140 of the control unit 110 when a value is exceeded. Note that the processing according to this flowchart may also be executed based on the above-described program control by the CPU. Note that the life flag in the SSD write count management table of the first SSD 141 is “0”. That is, it is assumed that the write count of the first SSD 141 has not reached the threshold value. Further, it is assumed that the processing from step S107 to step S109 described above has been completed.

  As shown in FIG. 7, when the control unit 110 writes data to the secondary cache 140, the control unit 110 first checks whether the data to be written to the secondary cache 140 is write data (step S201). When the data to be written is Read data (NO in Step S201), the control unit 110 controls to write the data from the data disk device 150 in the area 1412 of the first SSD 141 whose lifetime flag is “0” (Step S201). S202).

  If the data to be written is write data (YES in step S201), the control unit 110 further checks whether the size of the data to be written is smaller than the free space of the first SSD 141 whose life flag is “0” (step S203). . If the size of the data to be written is larger than the free space of the SSD 141 (NO in step S203), the control unit 110 controls to write the data to the data disk device 150 instead of the SSD 141 (step S204). When the size of the data to be written is smaller than the free space of the SSD 141 (YES in step S203), the control unit 110 stores the same data in the area 1411 and the buffer memory 160 of the first SSD 141 whose lifetime flag is “0”. Control is performed to write (step S205). Further, the control unit 110 refers to the copy management table stored in the storage unit 120 and checks whether the data address of the copy source information includes the address of the data controlled to be written to the area 1411 in step S205 (step S206). ). If there is any (YES in step S206), that is, if the writing of data to the area 1411 is overwriting and the data before overwriting has already been copied to the spare disk device 170, the control unit 110 sets the target data address. The data address of the buffer memory 160 into which the data was written in step S205 is written in the buffer memory information on the same line as (step S207). If there is not (NO in step S206), that is, if the data write to the area 1411 is new, the control unit 110 describes the address of the data written in the area 1411 in step S205 in the data address of the copy source information. In the memory information, the data address of the buffer memory 160 into which the data is written in step S205 is described (step S208).

  As shown in FIG. 8, the control unit 110 next checks whether data is stored in the buffer memory 160 and a write process is not performed on the first SSD 141 (step S209). If no data is stored in the buffer memory 160 or if the writing process is being performed on the first SSD 141 (NO in step S209), the control unit 110 ends the process of this operation as it is. If data is stored in the buffer memory 160 and no writing process is performed on the first SSD 141 (YES in step S209), the control unit 110 transfers the data stored in the buffer memory 160 to the spare disk device 170. (Step S210). Further, the control unit 110 searches the data address described in step S207 or step S208 from the data address of the buffer memory information, deletes the corresponding address, and sets the address of the spare disk device 170 that has copied the data to the copy destination information. This is described (step S211). Even when the address is already described in the copy destination information, the control unit 110 may update the copy destination information with the address of the spare disk device 170 that has copied the data.

  As described above, in the information storage device 1000, when the life flag in the SSD write count management table of the second SSD 142 is “1”, that is, when the write count of the second SSD 142 exceeds the threshold, The operation of controlling data writing to the next cache 140 is terminated.

  FIG. 9 is a block diagram illustrating a configuration of the information storage device 1000 after a new SSD is added to the secondary cache 140 in the information storage device 1000 according to the first embodiment. Here, it is assumed that the new SSD is the third SSD 143. FIG. 10 shows a redundant configuration in which a third SSD 143 is added to the secondary cache 140 in the information storage device 1000 according to the first embodiment, and data is copied from the first SSD 141 to the third SSD 143. It is a flowchart which shows the outline | summary of the operation | movement which builds. Note that the processing according to this flowchart may also be executed based on the above-described program control by the CPU. The life flag in the SSD write count management table of the first SSD 141 is set to “0”. That is, it is assumed that the write count of the first SSD 141 has not reached the threshold value. This operation can also be performed by a method in which the control unit 110 automatically recognizes that the third SSD 143 has been incorporated into the secondary cache 140 and starts the operation, and an operator manually inputs an operation start command from an input unit (not shown). It is also possible to use this method.

  As illustrated in FIG. 10, first, the control unit 110 divides the third SSD 143 into two regions in accordance with the ratio between the region 1411 and the region 1412 of the first SSD 141 (step S301). Here, an area for Write data of the third SSD 143 is an area 1431, and an area for Read data is an area 1432.

  Next, the control unit 110 refers to the SSD write count management table stored in the storage unit 120, adds the information of the third SSD 143, sets the same redundant configuration number as the first SSD 141, and sets the second redundancy configuration number. The redundant configuration number of the SSD 142 is deleted (step S302).

  Next, the control unit 110 copies all the data stored in the area 1411 of the SSD 141 to the area 1431 of the third SSD 143 (step S303).

  With the above, a new SSD is added to the secondary cache 140 in the information storage device 1000, data is copied from the first SSD 141 to the new SSD, and the operation of constructing a redundant configuration is completed.

  Next, effects of the first exemplary embodiment of the present invention will be described.

  The above-described information storage device 1000 according to the present embodiment can always store the secondary cache in a redundant manner without degrading performance.

  This is because the following configuration is included. That is, first, the control unit 110 duplicates only the SSD write data area of the secondary cache 140. This is because the read data always stores the original data in the data disk device 150, so that redundancy can be maintained without duplication as a secondary cache. Second, when writing the write data to the secondary cache 140 during the replacement of the SSD, the control unit 110 records the write data to be written in the remaining SSD and the buffer memory 160, which is a recording medium with high data processing speed, and then The data in the buffer memory 160 is copied to the spare disk device 170 as appropriate. As a result, even when the SSD is replaced, the control unit 110 can record the write data in a duplex manner on a recording medium with a high data processing speed, so that the secondary cache can always be made redundant and stored without performance degradation. .

[Modification]
Next, a modified example of the present invention will be described. Hereinafter, the description overlapping with the above description is omitted as long as the description of the present embodiment is not obscured.

  Instead of the buffer memory 160 in the first embodiment, write data may be recorded together with the remaining SSD in a partial area of the primary cache unit of the information storage device 1000 (not shown in FIG. 1). In this case, after the new SSD is added to the secondary cache 140 and the construction of the redundant configuration is completed, the area of the primary cache unit reserved for the buffer memory may be released.

  Further, the spare disk device 170 according to the first embodiment may be configured by an HDD of a device (not shown) that communicates with, for example, a tape drive or the information storage device 1000 instead of the HDD. This is because the spare disk device 170 is a device for temporarily forming a redundant configuration with the remaining SSD of the secondary cache 140, and performance is not required.

[Second Embodiment]
FIG. 11 is a block diagram showing a configuration of the information storage device 1001 in the second embodiment, which is the basic configuration of the first embodiment of the present invention. Referring to FIG. 11, the information storage device 1001 includes a control unit 111, a secondary cache 140, a data disk device 150, a buffer memory 160, and a spare disk device 170. The secondary cache 140 includes a first SSD 141 and a second SSD 142.

  The control unit 111 includes the function of the storage unit 120 in the first embodiment.

In addition, the information storage device 1001 in the second embodiment is specialized for the data write function of the secondary cache 140, reads the communication unit in the first embodiment that performs communication with the host device, reads data, Further, the data disk device in the first embodiment for further writing data from the secondary cache 140 is not considered. The effect of this embodiment described above is the same as the effect in the first embodiment.

  Although the present invention has been described with reference to each embodiment, the present invention is not limited to the above embodiment. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

100 Communication unit 110, 111 Control unit 120 Storage unit 140 Secondary cache 141, 142, 143 SSD
150 Data disk device 160 Buffer memory 170 Spare disk device 1000, 1001 Information storage device 1411, 1412, 1421, 1422, 1431, 1432

Claims (6)

A secondary cache unit configured by a plurality of SSDs (Solid State Drives), each SSD being divided into two areas, a write data area and a read data area;
Buffer memory,
A spare disk device as a storage medium;
Of the SSDs in the secondary cache unit , two SSDs are used to form a redundant configuration, the write data transfer destination is used as an area for write data of both SSDs, and the write count of each SSD in the redundant configuration is monitored and written. When an SSD whose number of times has reached the threshold is detected, the area for writing data of the other SSD is copied to the spare disk device, and the transfer destination of the writing data is set for the writing data of the other SSD. An information storage device comprising: an area and a control unit configured to copy the data set in the buffer memory and then transferred to the buffer memory to the spare disk device. The information storage device according to claim 1, wherein the control unit sets a transfer destination of the read data to a larger free space in the read data area of each SSD of the redundant configuration of the secondary cache unit . 3. The control unit according to claim 1, wherein , when the SSD detects an SSD in which the number of times of writing reaches a threshold value, the transfer destination of the read data is set as an area for read data of the other SSD of the secondary cache unit. The information storage device described. The control unit builds a redundant configuration with two SSDs of the secondary cache SSDs,
The transfer destination of the write data is an area for write data of both SSDs,
Monitor the number of writes of each SSD in the redundant configuration,
When detecting the SSD whose write count reaches the threshold value, copy the write data area of the other SSD to the spare disk device ,
Set the write data transfer destination in the write data area and buffer memory of the other SSD,
An information storage method for copying data transferred to the buffer memory to the spare disk device. The information storage method according to claim 4, wherein the control unit sets the transfer destination of the read data as a larger free space in the read data area of each SSD of the redundant configuration of the secondary cache.   6. The control unit according to claim 4 or 5, wherein when the control unit detects an SSD whose write count has reached a threshold value, the transfer destination of the read data is set as an area for read data of the other SSD of the secondary cache. Information storage method.

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