Efficient space accounting mechanisms for tracking unshared pages between a snapshot volume and its parent volume
US10732840B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 2018 |
| Grant date | Aug 4, 2020 |
| Priority date | — |
| Expiry date | Nov 9, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/067
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Techniques for tracking pages that are unshared among snapshot volumes and their parent volume in a volume family. The techniques include maintaining a first counter that tracks a first number (“SnapOwnedCount”) of pages among a total number of pages written to a volume that were overwritten in the immediate sequential next volume in the same branch as the volume, and a second counter that tracks a second number (“UnsharedWithParentCount”) of pages among the total number of pages written to the volume that were overwritten in any sequential next volume in the same branch as the volume. By maintaining, for each volume in a volume family, a first counter and a second counter for tracking the SnapOwnedCount and the UnsharedWithParentCount, respectively, data storage recovery can be performed more effectively, allowing selected volumes and/or portions thereof to be deleted while maintaining accurate space accounting information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.