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8.2. Choose a STONITH Device

It is crucial that your STONITH device can allow the cluster to differentiate between a node failure and a network failure.
A common mistake people make when choosing a STONITH device is to use a remote power switch (such as many on-board IPMI controllers) that shares power with the node it controls. If the power fails in such a case, the cluster cannot be sure whether the node is really offline, or active and suffering from a network fault, so the cluster will stop all resources to avoid a possible split-brain situation.
Likewise, any device that relies on the machine being active (such as SSH-based "devices" sometimes used during testing) is inappropriate.