[Linux-cluster] RHEL/CentOS-6 HA NFS Configuration Question

[Fabio M. Di Nitto]

On 05/15/2012 07:33 PM, Randy Zagar wrote:

>         	    <resources>
>         		    <ip address="192.168.1.1" monitor_link="1"/>
>         		    <ip address="192.168.1.2" monitor_link="1"/>
>         		    <ip address="192.168.1.3" monitor_link="1"/>
>         		    <fs device="/dev/cvg00/volume01" force_fsck="0" force_unmount="1" fsid="49388" fstype="ext3" mountpoint="/lvm/volume01" name="volume01" self_fence="0"/>
>         		    <fs device="/dev/cvg00/volume02" force_fsck="0" force_unmount="1" fsid="58665" fstype="ext3" mountpoint="/lvm/volume01" name="volume01" self_fence="0"/>
>         		    <fs device="/dev/cvg00/volume03" force_fsck="0" force_unmount="1" fsid="61028" fstype="ext3" mountpoint="/lvm/volume01" name="volume01" self_fence="0"/>
>         		    <nfsclient allow_recover="1" name="local-subnet" options="rw,insecure" target="192.168.1.0/24"/>
>         	    </resources>

For the <fs resources you want nfslock="1" option too.

>         	    <service autostart="1" domain="nfs1-domain" exclusive="0" name="nfs1" nfslock="1" recovery="relocate">
>         		    <ip ref="192.168.1.1">
>         			    <fs __independent_subtree="1" ref="volume01">
>         				    <nfsexport name="nfs-volume01">
>         					    <nfsclient name=" " ref="local-subnet"/>
>         				    </nfsexport>
>         			    </fs>
>         		    </ip>

For all services you need to change the order.

<fs..
 <nfsexport..
  <nfsclient..
   <ip..
  </nfsclient..
 </nfsexport..
</fs

This solves different issues at startup, relocation and recovery

Also note that there is known limitation in nfsd (both rhel5/6) that
could cause some problems in some conditions in your current
configuration. A permanent fix is being worked on atm.

Without extreme details, you might have 2 of those services running on
the same node and attempting to relocate one of them can fail because
the fs cannot be unmounted. This is due to nfsd holding a lock (at
kernel level) to the FS. Changing config to the suggested one, mask the
problem pretty well, but more testing for a real fix is in progress.

Fabio