Setting up CTDB on OCFS2 and VMs ...

[Martin Schwenke]

On Fri, 02 Jan 2015 12:57:14 +0000, Rowland Penny
<repenny241155 at gmail.com> wrote:

> OK, the lockfile now seems to work, at least I have a setting in 
> /etc/default/ctdb and both nodes are OK.
> 
> How have I managed this: well after reading something on a google link, 
> I did something, changed where 'CTDB_RECOVERY_LOCK' pointed to and it 
> now works.
> 
> What did I do???
> 
> I INSTALLED AND SETUP AN NFS SERVER ON ONE OF THE NODES!!!
> 
> Great, to use ctdb and samba (which is a way to share files), you have 
> to set up a separate way of sharing files.

Please stop.  You're embarrassing yourself and you're spreading
misinformation that people will find when they search for information
about running CTDB with OCFS2.

What you say is simply not true, apart from that fact that you need
lock coherency between the nodes to be able to use the recovery lock.
You have simply hacked a workaround that can apparently make the
recovery lock work.  To make the recovery lock work properly your
cluster filesystem needs lock coherency.  We have already discussed this
several weeks ago:

  https://lists.samba.org/archive/samba-technical/2014-December/104426.html

Nothing has changed.

It appears that getting lock coherency to work in OCFS2 is staggeringly
difficult.  Unfortunately, apart from Richard's work, we have no recipe
for setting up OCFS2 with lock coherence.  We can't tell you what
is wrong with your cluster except that CTDB's lock coherence test for
the recovery lock is failing.  Perhaps this is a topic that should be
taken to an OCFS2 mailing list?

How about we leave it at that and stop beating up on CTDB because a
particular filesystem doesn't (easily) provide a prerequisite feature?

We'll update CTDB so that it logs a clear message and aborts when the
lock coherence check fails during the first recovery.

Until then:

  http://dilbert.com/strips/comic/1995-06-24/

but s/computer/cluster filesystem/  - that is, why don't you try a
different cluster filesystem?  ;-)

peace & happiness,
martin