On-line restoration of redundancy information in a redundant array system
US5235601A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1990 |
| Grant date | Aug 10, 1993 |
| Priority date | — |
| Expiry date | Dec 21, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F11/1435
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for on-line restoration of redundancy information in a redundant array storage system. The invention provides alternative methods of restoring valid data to a storage unit after a Write failure caused by a temporary storage unit fault. In the first preferred method, a valid redundancy block is generated for the corresponding data blocks on all storage units. Resubmitting the interrupted Write operation causes the old (and potentially corrupted) data block to be "subtracted" out of the re-computed redundancy block. The uncorrupted new data block is written over the old data block, and is "added" into the recomputed redundancy block to create a new, corrected redundancy block. The new, corrected redundancy block is written to the appropriate storage unit. In the second preferred method, a new redundancy block is generated from all valid data blocks and the new data block. The new redundancy block and the new data block are then written to the appropriate storage units. In both cases, the entire method is done on-line, with insignificant interruption of normal operation of the redundant array system, and without requiring added processing during normal operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.