Using logical block addresses with generation numbers as data fingerprints for network deduplication

摘要

The technique introduced here involves using a block address and a corresponding generation number as a “fingerprint” to uniquely identify a sequence of data within a given storage domain. Each block address has an associated generation number which indicates the number of times that data at that block address has been modified. This technique can be employed, for example, to determine whether a given storage server already has the data, and to avoid sending the data to that storage server over a network if it already has the data. It can also be employed to maintain cache coherency among multiple storage nodes.

主权项

1. A method comprising:
determining that a first data block stored by a source device has been modified, that the first data block has the same content as a second data block on the source device, and that the first data block should be updated by a destination device; determining a block address of the second data block and a generation number of the block address, the generation number indicative of a number of times which data at the block address has been modified; and using the block address and the generation number to determine whether the destination device already has a data block that matches the block address and the generation number and to avoid sending the first data block to the destination device after determining that the destination device already has a data block that matches the block address and the generation number.