Method, apparatus for managing the redundant array of independent disks (RAID) and related computer readable medium

A device for managing a Redundant Array of Independent Disks (RAID), comprising:

• a processing unit;
• and
• a memory having instructions stored, the instructions, when executed by the processing unit, causing the device to perform acts of:
• in response to a stripe being created in the RAID, allocating to the stripe a storage space for storing a predetermined number of mapping information elements, the RAID being built on a plurality of extents divided from a plurality of disks, the stripe comprising a portion of the plurality of extents and a mapping information element of the stripe recording respective positions of extents included in the stripe at the plurality of disks;
• creating one or more mapping information elements for the stripe;
• storing the one or more mapping information elements in the storage space;
• allocating corresponding storage sequence numbers to the one or more mapping information elements stored in the storage space, to record an order in which each information element of the one or more mapping information elements is stored in the storage space;
• in response to receiving an I/O request for the stripe indicating one of the corresponding storage sequence numbers, accessing the stripe based on the mapping information element in the storage space that is corresponding to the storage sequence number indicated by the I/O request;
• and
• recording a storage sequence number allocated to a last mapping information element stored into the storage space, as a current storage sequence number.

A computer program product having a non-transitory computer readable medium which stores a set of instructions to manage a Redundant Array of Independent Disks (RAID);

• the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of:
• in response to a stripe being created in the RAID, allocating to the stripe a storage space for storing a predetermined number of mapping information elements, the RAID being built on a plurality of extents divided from a plurality of disks, the stripe comprising a portion of the plurality of extents, and a mapping information element of the stripe recording respective locations of extents comprised in the stripe at the plurality of disks;
• creating one or more mapping information elements for the stripe;
• storing the one or more mapping information elements in the storage space;
• allocating respective storage sequence numbers to the one or more mapping information elements stored in the storage space, to record an order in which each mapping information element of the one or more mapping information elements is stored in the storage space;
• in response to receiving an I/O request for the stripe indicating one of the respective storage sequence numbers, accessing the stripe based on the mapping information element in the storage space that is corresponding to the storage sequence number indicated by the I/O request;
• and
• recording a storage sequence number allocated to a last mapping information element stored into the storage space, as a current storage sequence number.