Mechanisms for performing accurate space accounting for volume families

Abstract

Techniques for performing space accounting for volume families. The techniques include maintaining two counters for each volume family, including a first counter that tracks a first amount of physical space allocated to volumes in the volume family based on the number of pages written to the volumes, and a second counter that tracks a second amount of physical space owned by the volume family, and maintaining a third counter for each volume in each branch of the volume family that tracks a number of pages among a total number of pages written to the volume that were overwritten in the immediate sequential next volume in the same branch as the volume. By maintaining, for each volume family, the first counter and the second counter, and, for each volume in the volume family, the third counter, space accounting metrics can be obtained that allow data storage activities to be performed efficiently.