Patent ID: 11960458
Assignee: EMC IP HOLDING COMPANY LLC
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 14:
15. A computer program product including a set of non-transitory, computer-readable media having instructions which, when executed by control circuitry of a data storage system, cause the control circuitry to perform a method of performing data deduplication, the method comprising:
providing a deduplication database, the deduplication database configured to store multiple entries that associate digest values computed from respective sub-blocks of data blocks with references to locations in the data storage system where data blocks containing the respective sub-blocks can be found;
implementing a policy for adding entries to the deduplication database, the policy specifying creation of new entries for first sub-blocks and last sub-blocks of data blocks but not for intermediate sub-blocks of those data blocks; and
processing a new data block for deduplication by (i) identifying multiple sub-blocks of the new data block, (ii) computing respective new digest values from the sub-blocks of the new data block, (iii) matching one of the new digest values to an entry in the deduplication database, and (iv) storing the new data block at least in part by reference to a target data block whose location is referenced by the matching entry.