[Pacemaker] offtopic scalable block-device

[Florian Haas]

On Fri, Mar 16, 2012 at 11:14 AM, Lars Marowsky-Bree <lmb at suse.com> wrote:
> On 2012-03-16T11:13:17, Florian Haas <florian at hastexo.com> wrote:
>
>> Which Ceph version are you using? Both the Ceph daemons and RBD are
>> fully integrated into Pacemaker in upstream git.
>>
>> https://github.com/ceph/ceph/tree/master/src/ocf
>>
>> You may want to look at http://www.hastexo.com/category/tags/ceph for
>> upcoming updates on this (RSS feed icon at the bottom).
>
> is there a reason for integrating ceph with pacemaker? ceph does
> internal monitoring of OSTs etc anyway, doesn't it?

Assuming you're referring to OSDs, yes it does. It does automatic
failover for MDSs (if you use them) and MONs too. But it currently has
no means of recovering an osd/mds/mon daemon in place when it crashes,
and that's what those RAs do. Really trivial.

Clearly, and the ceph devs and I agree on this, this is a stop-gap
until upstart or systemd jobs for the ceph daemons (with respawn
capability, of course) become widely available.

The ocf:ceph:rbd RA by contrast serves an entirely different purpose,
and I currently don't see how _that_ would be replaced by upstart or
systemd. Unless either of those becomes so powerful (and
cluster-aware) that we don't need Pacemaker at all anymore, but I
don't see that happen anytime soon.

Cheers,
Florian

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