[Linux-cluster] fencing device

Hofmeister, James (WTEC Linux) james.hofmeister at hp.com
Wed Dec 10 08:48:20 UTC 2008

Hello all,

|HP iLO is supported as a fencing device. If you are serious,
|you should still consider power fencing (don't forget, that
|fencing can be a SPOF, you need two fencing devices).

ILO is used on many sites successfully.

|iLO/IPMI fencing has some serious consequences:
|- It's not a shared device. It MUST be on the same network path as
|  heartbeat.

Not true...  I have my ILO on my public network and my heartbeat on a private network switch.  No problems with fencing in this configuration.

|- Server out of power = iLO out of power. After a recent update of cman
|  in RHEL5.2, rgmanager now waits for fencing to complete before
|  starting any services. If one node is offline (away for repair, etc.)
|  then it's fencing will never complete and you are stuck.

I have some ILO issues to be fixed in RHEL-5.3 for fencing on blades...   The situation I have seen is you must be successful in power off and power on for the ILO fence to complete as you suggest.  I hope this will would be changed and that a ILO power off would be sufficient.  In the case of "away for a planned repair" you would not perform an ILO fence, rather you would shutdown the node in the cluster gui.

I hope this helps.

  James Hofmeister (HP Linux).

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