STONITH is traditionally implemented by hardware solutions that allow a cluster to talk to a physical server without involving the operating system (OS). Although hardware-based STONITH works well, this approach requires specific hardware to be installed in each server, which can make the nodes more expensive and result in hardware vendor lock-in.
A disk-based solution, such as split brain detection (SBD), can be easier to implement because this approach requires no specific hardware. In SBD STONITH, the nodes in the Linux cluster keep each other updated by using a Heartbeat mechanism. If something goes wrong with a node in the cluster, the injured node will terminate itself.
See also: I/O fencing, Pacemaker