Data storage array employing block checksums and dynamic striping

A system, comprising:

• a plurality of storage devices configured in an array;
• and
• an array controller coupled to said plurality of storage devices, wherein said array controller is configured to store a first stripe of data as a first parity group comprising a first plurality of data stripe units across ones of said plurality of storage devices, and wherein said array controller is further configured to store a checksum for each of said first plurality of data stripe units;
• wherein said first plurality of data stripe units includes a first plurality of data blocks and a first parity block which is calculated for said first plurality of data blocks;
• wherein said array controller is configured to receive a write transaction modifying a subset of said first plurality of data blocks;
• wherein said array controller is configured to calculate a new parity block for said subset of said first plurality of data blocks modified by the write transaction;
• wherein, in response to the write transaction, said array controller is configured to store only said subset of said first plurality of data blocks modified by the write transaction and said new parity block as a new parity group to new locations across ones of said plurality of storage devices;
• and
• wherein said array controller is configured to store a new checksum for each block of said new parity group.

A method for storing data in a data storage subsystem, comprising:

• storing a first stripe of data as a first plurality of data stripe units across a plurality of storage devices;
• wherein said first plurality of data stripe units includes a first plurality of data blocks and a first parity block which is calculated for said first plurality of data blocks;
• storing entries in an indirection map for each data stripe unit, wherein each entry maps a virtual address to a physical address for one of the data stripe units, and wherein each entry further stores a checksum for the data stripe unit corresponding to that entry;
• receiving a write transaction specifying the virtual addresses of a subset of said first plurality of data blocks;
• calculating a new parity block for said subset of said first plurality of data blocks;
• storing only said subset of said first plurality of data blocks modified by the write transaction and said new parity block as a new parity group to new physical addresses across ones of said plurality of storage devices;
• and
• updating the entries in the indirection map for the data blocks modified by the write transaction to indicate the new physical address and checksum for each modified data block.

A method for storing data in a data storage subsystem, comprising:

• storing a first plurality of data stripe units across a plurality of storage devices, wherein said first plurality of data stripe units includes a first plurality of data blocks;
• storing entries in an indirection map for each data block, wherein each entry maps a virtual address to a physical address for one of the data blocks, and wherein each entry further stores a checksum for the data block corresponding to that entry;
• receiving a read request specifying the virtual addresses one of said first plurality of data blocks;
• accessing said indirection map to obtain the physical address mapped to the specified virtual address and to obtain the corresponding checksum;
• and
• in response to the read request, returning the data block at the physical address mapped to the specified virtual address and returning the corresponding checksum.