Providing parity in a RAID sub-system using non-volatile memory
US6988219B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 2002 |
| Grant date | Jan 17, 2006 |
| Priority date | — |
| Expiry date | Jan 19, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2211/1061
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention is a method for providing error correction for an array of disks using non-volatile random access memory (NV-RAM). Non-volatile RAM is used to increase the speed of RAID recovery from a disk error(s). This is accomplished by keeping a list of all disk blocks for which the parity is possibly inconsistent. Such a list of disk blocks is much smaller than the total number of parity blocks in the RAID subsystem. The total number of parity blocks in the RAID subsystem is typically in the range of hundreds of thousands of parity blocks. Knowledge of the number of parity blocks that are possibly inconsistent makes it possible to fix only those few blocks, identified in the list, in a significantly smaller amount of time than is possible in the prior art. The technique for safely writing to a RAID array with a broken disk is complicated. In this technique, data that can become corrupted is copied into NV-RAM before the potentially corrupting operation is performed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.