Virtual shared disks with application transparent recovery

A method for recovering from failures along a disk access path in a clustered computing system which includes at least three interconnected nodes wherein less than all nodes are server nodes and wherein each node includes a memory, and a multi-ported disk having at least a primary tail physically attached to a primary server node and a secondary tail physically attached to a secondary server node, comprising the steps of:

• detecting a failure in a disk access path in the clustered computing system, wherein a failed access path is associated with the primary tail;
• upon detection of the failure, a coordinator node broadcasting a message to all nodes of the system having access to the disk;
• each node receiving the message suspending access to the disk and acknowledging suspension of the access to the disk to the coordinator node;
• the coordinator node broadcasting a second message to the nodes to resume the access to the disk, responsive to said step of acknowledging suspension of the access to the disk;
• and
• each node receiving the second message, resuming the access to the disk by the secondary tail.

A clustered multi-processing system comprising:

• at least three interconnected nodes wherein less than all nodes are server nodes, each node including a memory;
• a multi-ported disk having at least a primary tail physically attached to a primary server node and a secondary tail physically attached to a secondary server node;
• a disk access request mechanism, coupled to the nodes, for communicating a disk access request from an originating node to a server node physically attached to the disk along one of at least a primary disk access path and a secondary disk access path defined between the originating node, the server nodes and the disk;
• a failure detection mechanism, coupled to the nodes, for detecting failures along one of the primary disk access path and the secondary disk access path;
• and,
• proxy logic means, coupled to the failure detection mechanism, for redirecting subsequent disk access requests via a two-phase commit protocol along a non-failing disk access path to the disk, when a failure is detected.