In a distributed system, a resource such as a storage device is protected by an owner node's exclusive access to it, wherein exclusive access is established via a persistent reservation on the resource. A persistent reservation is never removed, however the owner node's persistent reservation may be challenged in an arbitration process, to take it away from a failed owner node. A challenger node challenges by changing an owner's access key (that establishes the persistent reservation) to a challenge key, delaying, and determining whether the owner restored the owner's access key during the delay, because a properly operating owner replaces a challenge key with its owner access key. If the owner fails to restore its owner access key, the challenger node becomes the new resource owner by replacing the challenge key with an owner access key of the challenger node. The key may include additional information to provide extensibility.