Systems and methods for high availability computing systems. Systems and methods include disaster recovery of two-node computing clusters. A method embodiment commences upon identifying a computing cluster having two nodes, the two nodes corresponding to a first node and a second node that each send and receive heartbeat indications periodically while performing storage I/O operations. One or both of the two nodes detect a heartbeat failure between the two nodes, and in response to detecting the heartbeat failure, one or both of the nodes temporarily cease storage I/O operations. A witness node is accessed in an on-demand basis as a result of detecting the heartbeat failure. The witness performs a leadership election operation to provide a leadership lock to only one requestor. The leader then resumes storage I/O operations and performs one or more disaster remediation operations. After remediation, the computing cluster is restored to a configuration having two nodes.