Patent ID: 6862668
Filing Date: 2005-03-01
Classification: G06F,Y10S

Abstract:
1. A method for using cache coherency locking to facilitate on-line volume expansion in a multi-controller storage device, comprising: dividing a volume set into segments by a first controller; acquiring by the first controller a cache lock for one of the segments of the volume set to be expanded; and providing a second controller access to any non-cache-locked segments of data during the expansion while safeguarding integrity of the segment undergoing expansion, wherein the integrity of the data stored in the storage devices undergoing expansion being safeguarded comprises, prior to expansion of the cache-locked segment of the volume set, copying data of the cache-locked segment to a backup area and maintaining expansion data regarding the cache-locked segment in non-volatile memory and wherein the integrity of the data stored in the storage devices undergoing expansion being safeguarded further comprises making known to a second controller the expansion data.