Methods and devices for writing data in a disk array in storage system

A method (900) of writing data in a disk array (230) in a storage system (200), the method (900) comprising:

• in response to receiving from the disk array (230) a first request to allocate at least one cache page for caching to-be-written data, allocating the at least one cache page in a persistent memory (220) in a cache component (210) of the storage system (200), the to-be-written data being to be written into at least one storage block in at least one disk array group (231-1) in a degraded mode within the disk array (230);
• sending first information about the at least one cache page to the disk array (230);
• in response to receiving from the disk array (230) a first indication that the to-be-written data has been written into the at least one cache page, marking the at least one cache page as to-be-flushed;
• and
• sending to the disk array (230) a second indication that the to-be-written data can be flushed to the at least one disk array group (231-1), so that the to-be-written data in the at least one cache page marked as to-be-flushed is flushed into the at least one storage block.

A disk array (230) comprised in a storage system (200), the disk array (230) comprising:

• at least one processing unit;
• at least one memory coupled to the at least one processing unit and storing instructions executable by the at least one processing unit, the instructions, when executed by the at least one processing unit, causing a device to perform acts comprising:
• in response to receiving a write request to write new data to a data block in at least one disk array group (231-1) in a degraded mode within the disk array (230), reading old data stored in the data block and old parity information stored in a parity block associated with the data block;
• determining new parity information associated with the new data based on the old data, the old parity information, and the new data;
• writing the new data and the new parity information into at least one cache page provided by a cache component (210) in the storage system (200), the at least one cache page being allocated in a persistent memory (220) in the cache component (210);
• and
• flushing the new data and the new parity information into the data block and the parity block in the at least one disk array group (231-1), respectively.