[Pacemaker] unordered groups - is this safe to use?

[David Heidt]

Hello List,
let me first explain my environment:

* 2 Hosts with shared lvm-storage
* Debian Squeeze x64  with official squeeze heartbeat and pacemaker
* All resources are ocf:heartbeat:Xen
* One host is meant to host all production resources, the other is a hot-standby
* We want to run instant testing systems based on lvm snapshots on the
standby node.

This way, we can do heavy or dangerous tests without influencing the
production-host and taking advantage of the unused standby-hardware
In case of a hardware failure, all production resources have priority
(that is the colocation at the end)
To freely stop and restart resouces, i packed them into a group, but
no resource depends on another one, so the group has to be uncolocated
and unordered.
Finally i came to this setup:

<snip>

group grp_production rsc_1 rsc_2 \
meta ordered="false" collocated="false"

group grp_testing rsc_1_test rsc_2_test \
meta ordered="false" collocated="false"

colocation coloc_production_first -inf: grp_testing grp_production

</snip>

But following this thread makes me think of redesigning my crm setup:
http://oss.clusterlabs.org/pipermail/pacemaker/2011-January/008942.html

Quote Andrew Beekhof: "Unordered and/or uncolocated groups are an abomination."

What do you think? are resource_sets maybe a suitable alternative?

Regards,

David