[Pacemaker] Advisory ordering on clones not working?

Vladislav Bogdanov bubble at hoster-ok.com
Mon Feb 20 12:49:20 UTC 2012


20.02.2012 14:36, Andrew Beekhof wrote:
> On Mon, Feb 20, 2012 at 10:26 PM, Adrian Fita <adrian.fita at gmail.com> wrote:
>> Thanks, I figured it out by now. But the real problem I'm facing is
>> explained in http://oss.clusterlabs.org/pipermail/pacemaker/2012-February/013124.html
>> . Please also take a look there. This advisory thing was me trying to
>> solve the problem described in that message.
> 
> Ok, I see that thread.  I'll get to that one soon.

I now look at the similar case (advisory ordering doesn't work).

I hope I can add some pointers on what exactly happens.

Imagine you have two advisory-ordered resources each also depend
(colocated and mandatory ordered) on some other resource (f.e.
filesystem on drbd device Master state).
I now play with lustre filesystem. It consists of several parts:
* MGS (one per cluster, cluster can consist of several lustre filesystems)
* MDT (one per filesystem)
* OST (many per filesystem)
It is very important for lustre to operate properly that MDT is started
after MGS and OSTs started after MDT.

In my case I have MDT configured to start after MGS (advisory) and each
OST to start after MDT. Each of lustre parts is resided on a drbd device
(stacked one, so there is one more drbd device under it).

What I see after transition from stop-all-resources="true" to "false" is
that some OSTs (which are located on nodes different from where MDT is)
are started before MDT. I see that advisory ordering is not honored when
dependencies of "then" resource are satisfied before ones of "first"
resource.

hb_report?

Best,
Vladislav




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