Patent ID: 7849057

Claim:
A method for managing and organizing snapshots stored on a storage system, comprising: storing data in a plurality of volumes on the storage system; generating a snapshot for a selected volume of the plurality of volumes; allocating a snapshot identifier (snapid) for the selected volume, the snapid comprising an identifier that represents the snapshot and increases when another snapshot is generated for the selected volume; organizing metadata associated with snapshot data stored in one or more blocks of the snapshot within a data structure, wherein a particular field in the metadata indicates a most recent snapshot taken at a point in time when any block in an active region in a file system executing on the storage system was last written; denoting, by reading the snapid at a snapid field in the metadata for each block that is used in the snapshot, a newest snapshot for which each block is valid; and determining which blocks are valid for each snapshot using the snapid read from the snapid field.