Optimizing defragmentation operations in a differential snapshotter
US7664771B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 2003 |
| Grant date | Feb 16, 2010 |
| Priority date | — |
| Expiry date | Dec 29, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2201/84
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A differential snapshot is established and maintained for a set of files stored on a volume. Copy-on-write operations are avoided for logically insignificant moves of blocks, such as the block rearrangements characteristic of defragmentation utilities. A file system passes a block copy command to lower-level drivers that are to inform the snapshotter that a block move operation is not logically meaningful. When the logically insignificant move is of a block whose data forms part of the data captured in the snapshot virtual volume, and when the move is to a block location that is functioning as logical free space, the snapshotter can simply modify its block bitmap and update translation table entries without needing to perform a copy-on-write.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.