Method, system, apparatus, and computer-readable medium for taking and managing snapshots of a storage volume
US7373366B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 20, 2005 |
| Grant date | May 13, 2008 |
| Priority date | — |
| Expiry date | Oct 20, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2201/84
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method, system, apparatus, and computer-readable medium are provided for taking snapshots of a storage volume. According to aspects of one method, each snapshot is represented as a unique sequence number. Every fresh write access to a volume in a new snapshot lifetime is allocated a new section in the disk, called a provision, which is labeled with the sequence number. Read-modify-write operations are performed on a sub-provision level at the granularity of a chunk. Because each provision contains chunks with valid data and chunks with invalid data, a bitmap is utilized to identify the valid and invalid chunks with each provision. Provisions corresponding to different snapshots are arranged in a linked list. Branches from the linked list can be created for storing writable snapshots. Provisions may also be deleted and rolled back by manipulating the contents of the linked lists.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.