Storage system and control method of storage system including a storage control unit that performs a data amount reduction processing and an accelerator

1. A storage system comprising:

a plurality of storage control units;

an accelerator; and

a storage drive having a storage medium for storing data, wherein

each of the plurality of storage control units includes a processor and a memory,

metadata for accessing the data stored in the storage drive is held in a memory of a first storage control unit among the plurality of storage control units and a memory of a second storage control unit among the plurality of storage control units,

when a write request for updating the stored data is received, a processor of the first storage control unit

performs a data amount reduction processing of the data to be updated,

updates, by the data amount reduction processing, metadata related to the data to be updated, and

transmits the updated metadata and a processing request for the updated metadata to the accelerator, and

the accelerator stores the updated metadata in the memory of the first storage control unit and the memory of the second storage control unit based on the processing request for the updated metadata.

2. The storage system according to claim 1 , wherein

the processor of the first storage control unit transmits, in addition to the metadata, the recovery data including information for recovering metadata consistency and a processing request for the recovery data to the accelerator, and

the accelerator stores the recovery data in the memory of the first storage control unit and the memory of the second storage control unit based on the processing request for the recovery data.

3. The storage system according to claim 2 , wherein

the accelerator disables the recovery data in the memory of the first storage control unit and the recovery data in the memory of the second storage control unit after storing the metadata in the memory of the first storage control unit and the memory of the second storage control unit, and

the processor of the first storage control unit and the processor of the second storage control unit recover the metadata consistency based on enabled recovery data when storage of at least a part of the metadata in the memory of the first storage control unit and the memory of the second storage control unit is not normally completed.

4. The storage system according to claim 3 , wherein

the recovery data includes information for recovering the metadata to a state after the update of the metadata,

the accelerator disables the recovery data in the memory of the second storage control unit after storing the metadata in the memory of the first storage control unit and the memory of the second storage control unit, and then disables the recovery data in the memory of the first storage control unit.

5. The storage system according to claim 3 , wherein

the recovery data includes information for recovering the metadata to a state before the update of the metadata, and

the accelerator disables the recovery data in the memory of the first storage control unit after storing the metadata in the memory of the first storage control unit and the memory of the second storage control unit, and then disables the recovery data in the memory of the second storage control unit.

6. The storage system according to claim 1 , wherein

the metadata includes a correspondence relationship between a write destination logical address and a write destination physical address for accessing the data, and

the correspondence relationship is updated by the data amount reduction processing of the data to be written is performed.

7. The storage system according to claim 6 , wherein

the data amount reduction processing is a compression processing or a deduplication processing.

8. A control method of a storage system including a plurality of storage control units, an accelerator, and a storage drive having a storage medium for storing data, wherein

each of the plurality of storage control units includes a processor and a memory,

metadata for accessing the data stored in the storage drive is held in a memory of a first storage control unit among the plurality of storage control units and a memory of a second storage control unit among the plurality of storage control units, and

the control method comprising the steps of:

when a write request for updating the stored data is received, a processor of the first storage control unit

performing, by a processor of the first storage control unit, a data amount reduction processing of the data to be updated,

updating, by a processor of the first storage control unit, by the data amount reduction processing, metadata related to the data to be updated, and

transmitting, by a processor of the first storage control unit, the updated metadata and a processing request for the updated metadata to the accelerator, and

storing, by the accelerator, the updated metadata in the memory of the first storage control unit and the memory of the second storage control unit based on the processing request for the updated metadata.

9. The control method of the storage system according to claim 8 , wherein the control method further comprises the steps of:

transmitting, by the processor of the first storage control unit, in addition to the metadata, the recovery data including information for recovering metadata consistency and a processing request for the recovery data to the accelerator, and

storing, by the accelerator, the recovery data in the memory of the first storage control unit and the memory of the second storage control unit based on the processing request for the recovery data.

10. The control method of the storage system according to claim 9 , wherein the control method further comprises the steps of:

disabling, by the accelerator, the recovery data in the memory of the first storage control unit and the recovery data in the memory of the second storage control unit after storing the metadata in the memory of the first storage control unit and the memory of the second storage control unit, and

recovering, by the processor of the first storage control unit and a processor of the second storage control unit, the metadata consistency based on enabled recovery data when storage of at least a part of the metadata in the memory of the first storage control unit and the memory of the second storage control unit is not normally completed.

11. The control method of the storage system according to claim 10 , wherein

the recovery data includes information for recovering the metadata to a state after the update of the metadata, and

the accelerator disables the recovery data in the memory of the second storage control unit after storing the metadata in the memory of the first storage control unit and the memory of the second storage control unit, and then disables the recovery data in the memory of the first storage control unit.

12. The control method of the storage system according to claim 10 , wherein

the recovery data includes information for recovering the metadata to a state before the update of the metadata, and

the accelerator disables the recovery data in the memory of the first storage control unit after storing the metadata in the memory of the first storage control unit and the memory of the second storage control unit, and then disables the recovery data in the memory of the second storage control unit.

13. The control method of the storage system according to claim 8 , wherein

the metadata includes a correspondence relationship between a write destination logical address and a write destination physical address for accessing the data, and

the correspondence relationship is updated by the data amount reduction processing of the data to be written is performed.

14. The control method of the storage system according to claim 13 , wherein

the data amount reduction processing is a compression processing or a deduplication processing.