On-line reconstruction of a failed redundant array system
US5208813A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 23, 1990 |
| Grant date | May 4, 1993 |
| Priority date | — |
| Expiry date | Oct 23, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F11/14
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for on-line reconstruction of a failed storage unit in a redundant array system. After providing a replacement storage unit for the failed storage unit, reconstruction begins for each data stripe in the array. General reconstruction consists of applying an error-correction operation (such as an XOR operation on data blocks and a corresponding parity block) to the data blocks from the remaining storage units in the redundancy group, and storing the result in the corresponding block of the replacement storage unit. If a Read operation is requested by the CPU for a data block on the replacement storage unit, then a concurrent Read task is executed which reconstructs the stripe containing the requested data block. If a Read operation is requested by the CPU for a data block not on the replacement storage unit, a concurrent Read task is executed which performs a normal Read. If a Write operation is requested for any data block, then a concurrent Write task is executed which performs a Read-Modify-Write sequence in the general case (the Read operation being performed in accordance with the above rules).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.