Patent ID: 8433683

Claim:
A method of replicating a primary file system on a primary host to a secondary file system on a secondary host, comprising: determining a primary data block to replicate by reading a space map block entry (b, e) of the primary data block, wherein b represents a first snapshot and e represents a last snapshot to use the primary data block, wherein the primary data block is unchanged between b and e; computing a checksum of the primary data block of the primary file system to replicate on the secondary file system; determining a version of a most recent snapshot replicated to the secondary file system; sending the primary data block number from the primary host to the secondary host when the version of the most recent snapshot replicated to the secondary file system is equal to or greater than the version of b of the space map block entry (b, e); using a number of the primary data block to determine a secondary data block that corresponds to the primary data block; computing a checksum of the secondary data block of the secondary file system; comparing the primary and secondary data block checksums on the primary host or the secondary host; and replicating the primary data block on the secondary file system when the primary and secondary data block checksums mismatch, and repeating the above steps for the remaining data blocks of the primary file system, wherein the primary data block belongs to one or more snapshots of the primary file system.