Fully Replacing An Existing RAID Group Of Devices With A New RAID Group Of Devices

A data storage system comprising:

• a plurality of data storage devices (DSDs) configured for storing data chunks in a RAID (Redundant Array of Independent Disks);
• and
• a system controller circuitry comprising memory and one or more processors and embodying one or more sequences of instructions which, when executed by the one or more processors, cause performance of:
• marking a first group of the plurality of DSDs unavailable for write operations, while fulfilling all new write operations onto a second group of the plurality of DSDs and continuing to fulfill read operations from the first group;
• scanning a mapping of data chunk-to-RAID locations corresponding to all the DSDs of the first group;
• determining from the mapping that data is stored in a particular data chunk from the first group;
• in response to determining, transferring the data to the second group by:
• allocating storage space on the second group for storage of the data,
• copying the data in parallel from multiple DSDs of the first group to multiple DSDs of the second group, and
• upon completion of the copying of the data, updating the mapping to indicate where the data is stored on the second group;
• and
• marking the first group unavailable for further input/output (IO) operations.

A data storage system comprising:

• a plurality of data storage devices (DSDs);
• means for marking a first group of the plurality of DSDs unavailable for write operations, while fulfilling all new write operations onto a second group of the plurality of DSDs and continuing to fulfill read operations from the first group;
• means for scanning a mapping of data chunk-to-RAID locations corresponding to all the DSDs of the first group;
• means for determining from the mapping that data is stored in a particular data chunk from the first group;
• means for transferring the data to the second group in response to determining, including:
• means for allocating storage space on the second group for storage of the data,
• means for copying the data in parallel from multiple DSDs of the first group to multiple DSDs of the second group, and
• means for updating the mapping to indicate where the data is stored on the second group;
• and
• means for marking the first group unavailable for further input/output (IO) operations.