[Linux-cluster] ipmi fencing

Lon Hohberger lhh at redhat.com
Wed Jul 19 15:00:24 UTC 2006

On Wed, 2006-07-19 at 15:57 +1000, Jie Gao wrote:
> Hi All
> I am trialing clustering and GFS on RHEL AS U4. I am using the ipmi
> agent for fencing in a two-node setup.
> I have noticed that the agent sends "power off" to the node to be
> fenced. This is causes the node fenced to shut down uncleanly.
> I'd rather that it used the "power soft" option first and then used
> "power off" as the last resort.
> After all, what good use a corrupt system can serve?

Linux-cluster's I/O fencing is a very paranoid action taken to cut a
node off from shared data.

Letting a node try to gracefully shutdown - when we are not aware of why
the node is misbehaving - goes against the 'very paranoid' approach.  

Consider the case where a node has a double-bit memory problem, causing
quiet data corruption.  Letting it live a few extra seconds increases
the chance for more corrupt data.  Sure, it is rare, but how can we be
sure this *is not* the case when a node misbehaves?

-- Lon

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