Patent ID: 7302607

Claim:
A method for recovery in a two-node data processing system wherein each node is a primary server for a first disk drive and for which there is provided shared access to a second disk for which the other node is a primary server and wherein each node also includes a direct connection to the shared disk for which the other node is the primary server, said method comprising the steps of: receiving, at a first node, notification of communication failure with said second node; determining if said first node has access to the disk for which said first node is the primary server; shutting down recovery at said first node if said access is not present, but if it is present, accessing the disk for which said second node is the primary server via said hardware connection and waiting for a period of time sufficient to assure that recovery processes at said other node have completed past the same point as said first node; determining if said first node still has access to the disk for which it is the primary server and if said first node still has access, taking over control of the second node's disk; and if said first node doesn't have said access per said immediately preceding determining step, comparing node numbers to decide which node controls the other node's disks.