Patent ID: 7509473

Claim:
A storage system, comprising: a plurality of storage volumes; a storage controller, coupled to said plurality of storage volumes, said storage controller further comprising: a processor; a memory, coupled to said processor; and a system mapping table stored in said memory; wherein, for each of said plurality of storage volumes, said processor manages in said memory a respective volume mapping table, each entry of the volume mapping table associating a redundancy group with a storage unit of one of said plurality of storage volumes; at least one of said volume mapping tables is comprised of a plurality of segments of sequential segment number and logical block address range organized non-sequentially in the system mapping table; and each entry of the system mapping table being associated with a group of logical addresses via a hash value, each logical address being comprised of a volume number and a volume logical block address, the hash value resulting from the application of the volume number and a predetermined portion of the volume logical block address to a hash function.