초록 ▼

Provided herein is a method and apparatus for host transparent storage controller failover and failback. A controller is capable of assuming the identity of a failed controller while continuing to respond to its own SCSI ID or IDs in such a way that all SCSI IDs and associated units (LUNS) of the fa

Provided herein is a method and apparatus for host transparent storage controller failover and failback. A controller is capable of assuming the identity of a failed controller while continuing to respond to its own SCSI ID or IDs in such a way that all SCSI IDs and associated units (LUNS) of the failed controller are effectively taken over by the surviving controller. This "failover" behavior is transparent to any attached host computers and is treated by such attached hosts as a powerfail condition. The symmetric operation of returning the targets (IDs) and units (LUNs) to the previously failing controller ("failback") is likewise transparent.

대표청구항 ▼

[ What is claimed:] [2.] A method of performing a failback process in a computer system having a pair of storage controllers in a coupled configuration, wherein one of the storage controllers has failed, each storage controller of the pair coupled to the other storage controller by a communication l

[ What is claimed:] [2.] A method of performing a failback process in a computer system having a pair of storage controllers in a coupled configuration, wherein one of the storage controllers has failed, each storage controller of the pair coupled to the other storage controller by a communication link and connected to a host CPU by a SCSI bus, the surviving storage controller having IDs and units associated therewith, comprising the steps of:monitoring by the surviving one of the controllers the status of the failed controller;detecting by the surviving controller when the failed controller has been replaced with a replacement controller, the replacement controller reestablishing communications with the surviving controller over the communication link;restarting the replacement controller;checking for a configuration information mismatch between the surviving controller and the replacement controller by comparing configuration information stored in the replacement controller to configuration information stored in the surviving controller;if a mismatch is detected, then copying the configuration information stored in the surviving controller to the replacement controller;determining whether or not the surviving controller has any write-back cache data for one or more of the associated units that were owned by the failed controller prior to failure;flushing the write-back cache data to the one or more of the associated units; andreturning control of the one or more of the IDs and associated units belonging to the failed controller prior to failure to the replacement controller.