Patent ID: 7979395
Filing Date: 2011-07-12
Classification: G06F

Abstract:
1. A method comprising: creating a plurality of snapshots of data stored in a storage system, each of the snapshots using one or more blocks, wherein a particular snapshot is 010 invariant if each block in the snapshot is 010 invariant, and wherein a block is 010 invariant if, once that block becomes used, and later becomes unused, that block is not used again; storing the plurality of snapshots; selecting a set of snapshots to be deleted; determining, for the set of snapshots to be deleted, the number of blocks which are reclaimable if the set of snapshots are deleted, by determining the number of blocks which are exclusive to the set of snapshots to be deleted, wherein determining if a block is exclusive to the set of snapshots to be deleted includes: deleting the set of snapshots, said deleting including reclaiming those blocks that are exclusive to the set of snapshots.