Fencing (computing)

Fencing is the process of isolating a node of a computer cluster or protecting shared resources when a node appears to be malfunctioning.

As the number of nodes in a cluster increases, so does the likelihood that one of them may fail at some point. The failed node may have control over shared resources that need to be reclaimed and if the node is acting erratically, the rest of the system needs to be protected. Fencing may thus either disable the node, or disallow shared storage access, thus ensuring data integrity.