System and method for selective write-back caching within a disk array subsystem
US5572660A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 13, 1995 |
| Grant date | Nov 5, 1996 |
| Priority date | — |
| Expiry date | Nov 13, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2211/1009
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A fault tolerant disk array subsystem is provided that includes a plurality of data drives for storing real data and a parity drive for storing redundant data. Each data drive is associated with a dedicated write-through cache unit and the parity drive is associated with a dedicated write-back cache unit. An array scheduler schedules read and write operations to access the data drives and includes a parity control unit for updating parity information when new data is written to one of the data drives. Since a write-back caching technique is used to store updated parity information, the write latency of the parity drive does not limit the write-throughput of the disk array subsystem. Furthermore, since a non-volatile memory unit is provided to store the addresses of any dirty parity information within the write-back cache unit, parity information can be reconstructed in the event of a power failure. The disk array subsystem provides a low cost, mass storage resource having improved write performance characteristics. The disk array subsystem also accommodates data redundancy to allow data restoration in the event of disk failure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.