Amazon.com, Inc.
Storage volume snapshot object management

Abstract:

Systems and methods for durable storage of storage volume "snapshots" are provided. Snapshots are stored as collections of snapshot data objects. To improve the durability of snapshot storage, physical deletion of snapshot data objects may be delayed for a period of time after the snapshot data objects are marked for deletion. Lists of the stored snapshot data objects and the snapshot data objects that make up active snapshots may be periodically analyzed. If there are any snapshot data objects that are part of active snapshots and are not present in the list of stored snapshot data objects, the snapshot data objects may be recovered before they are physically deleted.