[CentOS] HP ILO Fence Configuration

Tue Aug 5 21:45:35 UTC 2008
John R Pierce <pierce at hogranch.com>

> What about configuring a cluster without fencing? is it possible? I am 
> about to create a cluster but with out fencing device.

Generally its dangerous.   if the servers get out of sync and both try 
to mount a shared resource, you can end up with corrupted file 
systems.   since the primary goal of a high availability cluster is, 
well, high availability, and increased overall system reliability, these 
clusters have to be constructed very carefully or they can cause more 
problems than they solve.

what sort of shared resources will this HA cluster have?    how is the 
shared storage connected ?    if its via a iSCSI SAN, you can implement 
fencing via either the ethernet switch (tell the switch to drop the 
standby server from the iscsi vlan), or via the storage controller (tell 
the iscsi target host to disallow LUN access by the current standby 
server).   If its a fiberchannel SAN you can fence via the SAN switch.