Method and system for service-aware parity placement in a storage system

A system, comprising:

• a storage array comprising a plurality of storage devices (SDs);
• and
• a storage controller operatively connected to the storage array and configured to:
• identify a target SD to remove;
• after identifying the target SD, wherein the target SD is one of the plurality of SDs:
• receive a request to write data to the storage array;
• in response to the request, write a Redundant Array of Independent Disks (RAID) stripe to persistent storage, wherein the RAID stripe comprises data blocks and a first parity block, wherein at least one of the data blocks comprises a portion of the data, wherein the first parity block comprises a parity value calculated using the data blocks, and wherein the first parity block is stored on the target SD and wherein none of the data blocks are stored on the target SD;
• perform a modified garbage collection operation, wherein the modified garbage collection operation comprises:
• identifying a live RAID stripe in the persistent storage, wherein the live RAID stripe comprises second data blocks and a second parity block;
• writing a new RAID stripe to a new location in the persistent storage, wherein the new RAID stripe comprises a third parity block and third data blocks, wherein at least one of the third data blocks stores a copy of a portion of data from the live RAID stripe, wherein the third parity block is stored on the target SD, and wherein none of the third data blocks is stored on the target SD;
• and
• issue a removal notification when the modified garbage collection operation is completed, wherein the removal notification indicates that the target SD may be removed from the storage array.

A non-transitory computer readable medium comprising instructions, which when executed by a processor perform a method, the method comprising:

• receiving a service notification specifying a target storage device (SD), wherein the target SD is one of plurality of SDs;
• after receiving the service notification:
• receiving a request to write data to persistent storage, wherein the persistent storage comprises the plurality of SDs;
• in response to the request, writing a Redundant Array of Independent Disks (RAID) stripe to the persistent storage wherein the RAID stripe comprises data blocks and a first parity block, wherein at least one of the data blocks comprises a portion of the data, wherein the first parity block comprises a parity value calculated using the data blocks, and wherein the parity block is stored on the target SD and wherein none of the data blocks are stored on the target SD;
• performing a modified garbage collection operation, wherein the modified garbage collection operation comprises:
• writing a new RAID stripe to a new location in the persistent storage, wherein the new RAID stripe comprises a copy of a first data from a first live RAID stripe and a copy of second data from a second live RAID stripe in the storage array, and wherein the new RAID stripe comprises a second parity block located on the target SD;
• and
• issuing a removal notification when the modified garbage collection operation is completed, wherein the removal notification indicates that the target SD may be removed from the persistent storage.