Patent ID: 8117158
Filing Date: 2012-02-14
Classification: G06F,Y10S

Abstract:
1. A method for managing the snapshots for a data storage volume, the method comprising: maintaining a data structure for one or more provisions in the data storage volume, the data structure comprising a first data field, a second data field, and a third data field; storing a sequence number in the first data field that identifies a snapshot lifetime in which the provision was written, wherein the sequence number of each snapshot lifetime is an increasing value that uniquely identifies the snapshot lifetime; storing a bitmap in the second data field that identifies the portions of the provision that were written during the snapshot lifetime identified by the first data field; storing a pointer to a next data structure for another snapshot lifetime for the provision in the third data field; receiving a request to delete a snapshot, the snapshot to be deleted identified by a sequence number; and deleting the snapshot by manipulating only the data structures for the one or more provisions in accordance with a comparison of the sequence number of the snapshot to be deleted and sequence numbers of the one or more provisions, and resetting a bit in a data structure having a prior sequence number than the sequence number of the snapshot to be deleted if the bit is identified in a data structure having a newer sequence number than the sequence number of the snapshot to be deleted.