NFS Cluster Failover

[Richard Bailey]

Hello,

We are currently deploying some servers in a failover situation for high
availability using RHEL AS 3. I have followed the Red Hat Cluster Suite:
Configuring and Managing a Cluster guide to set up a clustered NFS
service, but failover just does not happen.

We have two nodes, hydradb4 and hydradb5 with a virtual ip that maps to
the name hydradb. They both have access to a shared disk /dev/emcpowera3
with /dev/emcpowera1 and /dev/emcpowera2 being the raw devices for the
cluster shared state. At this stage I can easily move the service
between the two nodes with no problem and the disk moves with it with
ease.

/dev/emcpowera3 is now being mounted on /export/oracle/PRD/920_32 and is
being shared over nfs as /export/oracle/PRD/920_32. Again, I can move
the service safely from node to node without a problem.

When any host has hydradb:/export/oracle/PRD/920_32 mounted however, if
I try to move or stop the service I get an error:
<err> service error: 'umount /dev/emcpowera3' failed
(/export/oracle/PRD/920_32 ), error=1
<err> service error: umount: /export/oracle/PRD/920_32: device is busy
<err> service error: umount: /export/oracle/PRD/920_32: device is busy
<err> service error: Cannot stop filesystems for hydradb

I have the Force Unmount option checked for the nfsexport in the service
as recommended.

Does this error sound familiar? Does anyone know how I can get the
clustered nfs service to work as advertised?

- Thanks in advance,
Richard Bailey,
Technical Analyst