Patent ID: 6810491
Filing Date: 2004-10-26
Classification: G06F

Abstract:
A multiple disk system having a failover component, the system comprising:plural input-output (I/O) ports; plural disk groups, each disk group comprising plural disk drive units, each disk group being arranged into one or more logical volumes, each logical volume comprising at least two of said disk drive units, a first of said logical volumes being a primary volume and one or more others of said logical volumes being secondary volumes; a disk controller operatively coupled to each of said I/O ports to receive I/O requests from one or more host systems, said disk controller configured to read and write data to said primary volume and to copy said data to one or more of said secondary volumes to satisfy said I/O requests, wherein data that is written to said primary volume is mirrored to said one or more of said secondary volumes; and a detector operable with said disk controller to detect when a disk group has become unavailable, said detector further configured to determine whether an unavailable disk group includes said primary volume and if so to select one of said secondary volumes as a replacement volume, said replacement volume being in an available disk group.