Methods and structure for maintaining cache consistency in a RAID controller having redundant caches
US5761705A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 1996 |
| Grant date | Jun 2, 1998 |
| Priority date | — |
| Expiry date | Apr 4, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0815
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Methods and associated apparatus operable in a RAID subsystem having redundant disk array controllers to assure dual, redundant cache consistency while permitting operation of the RAID subsystem in response to host computer I/O requests. The methods and apparatus of the present invention provide for a process of initializing the redundant disk array controllers in response to a power-on reset cycle (or other similar reset cycles). The first controller partially initializes for processing of host requests then awaits the partial initialization of the second controller. After a brief timeout awaiting the second controller, or in response to an erroneous initialization of the second controller, the first controller configures itself to perform host computer I/O requests in a write-through mode (bypassing cache operations) until the second controller eventually initializes. Once both controller are initialized, the redundant caches are synchronized. Finally, the initialized controllers having synchronized the redundant caches begin normal, mirrored, redundant operation. Until such time as the redundant caches are synchronized, the first controller continues operations in response to ho…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.