[Pacemaker] DRBD+LVM+NFS problems

Dennis Jacobfeuerborn dennisml at conversis.de
Tue Mar 26 13:21:47 EDT 2013

On 26.03.2013 06:14, Vladislav Bogdanov wrote:
> 26.03.2013 04:23, Dennis Jacobfeuerborn wrote:
>> I have now reduced the configuration further and removed LVM from the
>> picture. Still the cluster fails when I set the master node to standby.
>> What's interesting is that things get fixed when I issue a simple
>> "cleanup" for the filesystem resource.
>> This is what my current config looks like:
>> node nfs1 \
>>      attributes standby="off"
>> node nfs2
>> primitive p_drbd_web1 ocf:linbit:drbd \
>>      params drbd_resource="web1" \
>>      op monitor interval="15" role="Master" \
>>      op monitor interval="30" role="Slave"
>> primitive p_fs_web1 ocf:heartbeat:Filesystem \
>>      params device="/dev/drbd0" \
>>      directory="/srv/nfs/web1" fstype="ext4" \
>>      op monitor interval="10s"
>> ms ms_drbd_web1 p_drbd_web1 \
>>      meta master-max="1" master-node-max="1" \
>>      clone-max="2" clone-node-max="1" notify="true"
>> colocation c_web1_on_drbd inf: ms_drbd_web1:Master p_fs_web1
> Above means: "colocate ms_drbd_web1:Master with p_fs_web1", or "promote
> ms_drbd_web1 where p_fs_web1 is (or "is about to be")".
> Probably that is not exactly what you want (although that is also valid,
> but uses different logic internally). I usually place resources in a
> different order in colocation and order constraints, and that works.

Indeed I had the colocation semnatics backwards. With that change the 
failover work correctly, thanks!

I still have problems when using LVM although these don't seem to be 
pacemaker related. I have defined /dev/drbd0 with a backing device 
/dev/vdb. The problem is that when I create a physical volume on 
/dev/drbd0 and do a pvs the output shows the physical volume on /dev/vdb 
instead. I already disabled caching in /etc/lvm/lvm.conf, prepended a 
filter "r|/dev/vdb.*|" and recreated the initramfs and reboot but LVM 
still sees the backing device as the physical volume and not the 
actually replicated /dev/drbd0.

Any idea why LVM is still scanning /dev/vdb for physical volumes despite 
the filter?


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