Apparatus and method for changing the cache mode dynamically in a storage array system
US5815648A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 14, 1995 |
| Grant date | Sep 29, 1998 |
| Priority date | — |
| Expiry date | Nov 14, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0866
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for changing the cache mode of a volume in response to user commands or detection of a failure within the storage system. Specifically, the method applies the new cache mode to all newly issued I/O requests, while retaining the old cache mode for previously unfinished or queued I/O requests. The method incorporates a cache mode field to the I/O request data structure. The cache mode field specifies the cache mode to be used for that I/O request. The method initializes the I/O request cache mode field with the value of the cache mode field of the corresponding target volume. When the cache mode of a volume is changed, all subsequent I/O requests to the volume are tagged with the new cache mode in their cache mode field. However, previous I/0 requests will retain the former cache mode and will be completed using the former cache mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.