Arbitration of disk ownership in a storage pool

The present invention extends to methods, systems, and computer program products for implementing persistent reservation techniques for establishing ownership of one or more physical disks. These persistent reservation techniques can be employed to determine ownership of physical disks in a storage pool as well as in any other storage configuration. Using the persistent reservation techniques of the present invention, when a network partition occurs, a defender of a physical disk does not remove a challenger's registration key until the defender receives notification that the challenger is no longer in the defender's partition. In this way, pending I/O from applications executing on the challenger will not fail due to the challenger's key being removed until the proper ownership of the physical disk can be resolved.