System and method for growing differential file on a base volume of a snapshot
US6473775B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 2000 |
| Grant date | Oct 29, 2002 |
| Priority date | — |
| Expiry date | Feb 16, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2201/84
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system and method for creating a snapshot with a differential file maintained on the base volume that can grow as needed. When a snapshot is captured, free space is allocated on the base volume to receive the differential file. Writes to the base volume are allowed except to the free space allocated to the differential file. Then the snapshot is captured. After the snapshot process is complete, data that was originally present at the time the snapshot was captured may be copied to the differential file before it is modified. To grow the differential file out of its allocated space, new free space is selected from the free space currently on the base volume in conjunction with the free space at the time the snapshot was captured. The free space bitmap file of the snapshot volume may be used to identify the free space at the time the snapshot was captured.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.