Storage control device and non-transitory computer-readable storage medium for storing storage control program

1. A storage control device comprising:

an auxiliary cache memory that is a nonvolatile memory;

a volatile memory; and

a processor configured to:

execute a writing control process that including

receiving a first command to write first data to a storage medium with a lower processing speed than the auxiliary cache memory and a larger capacity than the auxiliary cache memory,

writing the first data to the volatile memory,

transmitting a response indicating the completion of the writing,

writing the first data stored in the volatile memory to the auxiliary cache memory after the transmission of the response, and

writing the first data stored in the auxiliary cache memory to the storage medium;

execute an information management process that includes storing management information in the volatile memory, the management information including state information indicating storage states of data in the auxiliary cache memory and in the storage medium; and

execute a saving control process after a predetermined failure occurs, the saving control process being configured to

cause the writing control process to stop control of writing the data stored in the auxiliary cache memory to the storage medium,

secure, in the auxiliary cache memory, a storage region for storing the management information of the volatile memory,

generate a copy of the management information of the volatile memory in the storage region, and

cause the writing control process to execute control to write the first data stored in the volatile memory to the auxiliary cache memory or the storage medium based on the management information of the auxiliary cache memory.

2. The storage control device according to claim 1 , wherein

the writing controller is configured to,

after the predetermined failure occurs,

receive a second command to write second data to the storage medium,

write the second data to the volatile memory,

select either the auxiliary cache memory or the storage medium based on the storage state of the data of the auxiliary cache memory,

write the second data stored in the volatile memory to the selected auxiliary cache memory or the selected storage medium, and

transmit a response indicating the completion of the writing.

3. The storage control device according to claim 2 , wherein

when first update data exists at a time the predetermined failure occurs, the writing control process is configured to use the first update data to update the first data before the reflection, the first data before the reflection being data that has been stored in the auxiliary cache memory and that has not yet been stored in the storage medium, the first update data being data that corresponds to the first data before the reflection and that has been stored in the volatile memory and that has not been stored in the auxiliary cache memory.

4. The storage control device according to claim 3 , wherein

when the received second command is a command to update the first data before the reflection, the writing control process is configured to

select the auxiliary cache memory, and

write the second data stored in the volatile memory to the selected auxiliary cache memory.

5. The storage control device according claim 2 , wherein

when second update data exists at a time the predetermined failure occurs, the writing control process is configured to delete information of the reflected first data included in the management information and use the second update data to update the reflected first data stored in the storage medium, the reflected first data being data that has been stored in both of the auxiliary cache memory and the storage medium, the second update data that corresponds to the reflected first data and that has been stored in the volatile memory and that has not yet been stored in the auxiliary cache memory.

6. The storage control device according to claim 5 , wherein

when the received second command is a command to update the reflected first data, the writing control process is configured to

select the storage medium, and

write the second data stored in the volatile memory to the selected storage medium.

7. The storage control device according to claim 1 , wherein

when the predetermined failure occurs, the writing control process is configured to

reference the management information, and

acquire writing states of the first data in the auxiliary cache memory and the storage medium based on the state information.

8. A non-transitory computer-readable storage medium for storing a storage control program for controlling a storage device, the storage device including an auxiliary cache memory, a volatile memory, and storage medium, the auxiliary cache memory being a nonvolatile memory, the storage medium being a medium with a lower processing speed than the auxiliary cache memory and a larger capacity than the auxiliary cache memory, the storage control program being configured to cause a processor to execute a process, the process comprising:

executing a writing control process configured to

receive a command to write first data to the storage medium,

write the first data to the volatile memory,

transmit a response indicating the completion of the writing,

write the first data stored in the volatile memory to the auxiliary cache memory after the transmission of the response, and

write the first data stored in the auxiliary cache memory to the storage medium;

executing an information management process configured to store, in the volatile memory, management information having registered state information indicating storage states of data in the auxiliary cache memory and the storage medium;

executing a saving control process after a predetermined failure occurs, the saving control process being configured to

stop control of the writing of the data stored in the auxiliary cache memory to the storage medium,

secure, in the auxiliary cache memory, a storage region for storing the management information of the volatile memory,

generate a copy of the management information of the volatile memory in the storage region, and

write the first data stored in the volatile memory to the auxiliary cache memory or the storage medium based on the management information of the auxiliary cache memory.