Method and system for copying a snapshot tree
US7788244B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 2007 |
| Grant date | Aug 31, 2010 |
| Priority date | — |
| Expiry date | Jul 23, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2201/84
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Various embodiments of the present invention are directed to an instant snapshot-tree-copy operation that, when directed to an existing snapshot tree, generates a data-structure framework for a copy of the existing snapshot tree that can be immediately accessed while a background-copy process copies data from the existing snapshot tree to the copy snapshot tree. The background-copy process copies data from the existing snapshot tree to the copy snapshot tree in top-down fashion, from the source logical device through each of the snapshot logical devices. While copying each logical device, the background-copy process sequentially copies data-storage units from a corresponding logical device of the existing snapshot tree to the copy-snapshot-tree logical device, making sure to adjust chains of dependencies within the copy snapshot tree to reflect modifications to the snapshot copy tree that occur independently from the background-copy process. A host computer may immediately access the copy snapshot tree, both for READ and WRITE access, even before completion of the background-copy process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.