An apparatus is disclosed for deterministically performing active-active failover of redundant servers in response to a failure of a link on which each server provides a heartbeat to the other server. Each of the servers is configured to take over the identity of the other server on a common network in response to detecting a failure of the other server's link heartbeat. Each server provides a status indicator to a storage controller indicating whether the other server's link heartbeat stopped. The storage controller determines the link has failed if both of the status indicators indicate the other server's heartbeat stopped, and responsively kills one of the servers. The storage controller also receives a heartbeat directly from each server. If only one direct heartbeat stops when the status indicators indicate the link heartbeats stopped, then the storage controller detects one server has failed and inactivates the failed server.