Overview of Multiple or Redundant Fencing
Redundant or multiple fencing is where fencing methods are combined. This is sometimes also referred to as “nested fencing”.
For example, as first level fencing, one fence device can cut off Fibre Channel by blocking ports on the FC switch, and a second level fencing in which an ILO interface powers down the offending machine.
You add different fencing levels by using pcs stonith level.
All level 1 device methods are tried first, then if no success it will try the level 2 devices.
pcs stonith level add <level> <node> <devices>
pcs stonith level add 1 centos1 fence_centos1_ilo
pcs stonith level add 2 centos1 fence_centos1_apc
to remove a level use:
pcs stonith level remove
to view the fence level configurations use
pcs stonith level