Patent ID: 8260744
Filing Date: 2012-09-04
Classification: G06F,Y10S

Abstract:
1. A data storage system comprising: a physical data storage device containing a data storage volume; and a computerized controller operable for taking snapshots of a data storage volume, and for 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, wherein the computerized controller stores an increasing sequence number in the first data field that identifies a snapshot lifetime in which the provision was written and whether the identified snapshot lifetime is a read-write snapshot lifetime or a read-only snapshot lifetime, each snapshot lifetime being associated with a different increasing sequence number, stores a bitmap in the second data field that identifies portions of the provision that were written during the snapshot lifetime identified by the first data field, and stores a pointer to a next data structure for another snapshot lifetime for the provision in the third data field.