Hi,

I am experiencing an error situation which gets not detected by the cluster.

I created a 2-node cluster using drbd and want to use ocfs2 on both nodes 
simultaneously. (stripped off some monitor/meta stuff)

primitive dlm ocf:pacemaker:controld
primitive o2cb ocf:ocfs2:o2cb
primitive resDRBD ocf:linbit:drbd \
        params drbd_resource="r0" \
        operations $id="resDRBD-operations"
primitive resource-fs ocf:heartbeat:Filesystem \
        params device="/dev/drbd_r0" directory="/SHARED" fstype="ocfs2"
ms msDRBD resDRBD
clone clone-dlm dlm
clone clone-fs resource-fs
clone clone-ocb o2cb
colocation colocation-dlm-drbd inf: clone-dlm msDRBD:Master
colocation colocation-fs-o2cb inf: clone-fs clone-ocb
colocation colocation-ocation-dlm inf: clone-ocb clone-dlm
order order-dlm-o2cb 0: clone-dlm clone-ocb
order order-drbd-dlm 0: msDRBD:promote clone-dlm:start
order order-o2cb-fs 0: clone-ocb clone-fs

The cluster starts up happily. (everything green in crm_gui) but

rt-lxcl9a:~ # drbd-overview
  0:r0/0  WFConnection Primary/Unknown UpToDate/DUnknown C r-----
rt-lxcl9b:~ # drbd-overview
  0:r0/0  StandAlone Primary/Unknown UpToDate/DUnknown r-----

As you can see this is a split brain situation with both nodes having the ocfs2 
fs mounted but not in sync --> data loss will happen.

1.      How to avoid split brain situations (I am confident that the cross link 
using a 10GB cable was never interrupted)?
2.      How to resolve this?
Switch cluster in maintenance mode and then follow 
http://www.drbd.org/users-guide/s-resolve-split-brain.html ?
3.      How to make the cluster aware of the split brain situation? (It thinks 
everything is fine)
4.      Should the DRBD(OCFS2 setup be maintained outside the cluster instead?

Mit freundlichen Grüßen / Best regards

Martin Konold

Robert Bosch GmbH
Automotive Electronics
Postfach 13 42
72703 Reutlingen
GERMANY
www.bosch.com<http://www.bosch.com>

Tel. +49 7121 35 3322

Sitz: Stuttgart, Registergericht: Amtsgericht Stuttgart, HRB 14000;
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