STORAGE SYSTEM AND DATA PROTECTION METHOD

1 . A storage system comprising:

a non-volatile storage device; and

a plurality of storage controllers that control reading and writing for the storage device, wherein

the storage device is a user data storage drive,

each of the plurality of storage controllers includes a processor and a memory,

the storage controller includes a first memory protection method that is a memory copying method of copying data on the memory to a memory of a corresponding storage controller and a second memory protection method that is a log saving method of generating a log related to update of the data on the memory and writing the log into a non-volatile medium,

the storage controller stores a write request from a host for the storage device as cache data in the memory, returns a write completion response to the host after protecting the cache data in the first memory protection method or the second memory protection method, and destages the cache data into the storage device after the write completion response, and

the storage controller switches between the first memory protection method and the second memory protection method to be used according to an operation state of another storage controller.

2 . The storage system according to claim 1 , wherein

the storage controller is associated with another storage controller to form a redundant configuration, and is used in the first memory protection method, and is used in the second memory protection method in a case where the corresponding storage controller is failed.

3 . The storage system according to claim 2 , wherein

the non-volatile medium in which the log is written is provided inside the storage controller.

4 . The storage system according to claim 2 , wherein

a part of the non-volatile storage device is used as the non-volatile medium in which the log is written.

5 . The storage system according to claim 1 , wherein

in the destage, the data is stored in a final storage area of the storage device by using a storage function provided by the storage system.

6 . The storage system according to claim 2 , wherein

in a case where it is detected that the corresponding storage controller is failed, the storage controller performs operation switching from the memory copying method to the log saving method, preferentially destages pre-switching cache data that is cache data before the operation switching into the storage device, and destages post-switching cache data that is cache data after the operation switching, after destaging all the pre-switching cache data, and

in a case where recovery from the failing of the corresponding storage controller is detected, the storage controller copies the data on the memory to the memory of the corresponding storage controller, deletes the log, and performs operation switching from the log saving method to the memory copying method.

7 . A data protection method of a storage system including a non-volatile storage device and a plurality of storage controllers that control reading and writing for the storage device, wherein

the storage device is a user data storage drive, and

each of the plurality of storage controllers includes a processor and a memory, and

the storage controller includes a first memory protection method that is a memory copying method of copying data on the memory to a memory of a corresponding storage controller and a second memory protection method that is a log saving method of generating a log related to update of the data on the memory and writing the log into a non-volatile medium,

the data protection method comprising:

storing, by the storage controller, a write request from a host for the storage device in the memory as cache data;

protecting, by the storage controller, the cache data in the first memory protection method or the second memory protection method;

returning, by the storage controller, a write completion response to the host;

destaging, by the storage controller, the cache data into the storage device after the write completion response; and

switching, by the storage controller, between the first memory protection method and the second memory protection method to be used according to an operation state of another storage controller.