[Pacemaker] [DRBD-user] DRBD is not syncing over my routed network.

[Andrew Beekhof]

On Wed, Sep 9, 2009 at 3:16 PM, Florian Haas<florian.haas at linbit.com> wrote:
> [CCing the Pacemaker list here, in case we have people interested in
> following this discussion there]
>
> On 09/08/2009 05:52 PM, Gary.Webb at opengi.co.uk wrote:
>> Hi.      I am having a problem whilst carrying out some preliminary
>> testing of DRBD with OpenAIS.  My test setup was all working fine. I
>> have now introduced it to a simulated wide area network by changing the
>> subnet on each system, modifying the config files accordingly, adding
>> the relevant routes and gateway, and using an established Linux box that
>> we use for throttling bandwidth for such testing. The network config is
>> sound as I can ping to and from each node through the router system. I
>> also have full key authentication setup between them. Nothing else has
>> changed.
>
> Gary,
>
> If you actually get this to work with OpenAIS, be sure to let us know
> and share your findings. AFAICS this is bound to fail as OpenAIS
> currently isn't capable of unicast messaging, so unless you actually
> manage to get multicast routing set up correctly between your sites,
> you're out of luck.

bcast is also an option for more recent releases.

> The Heartbeat communication stack does support
> unicast, but it too requires that you have super-reliable links between
> sites. And, regardless of the communication layer beneath it, Pacemaker
> currently does not support split-site clustering.

Not well anyway.  You can kludge something together, but its not at all pretty.

> If you want to do a split-site setup with what is available today, then
> that effectively amounts to having two separate clusters, which happen
> to share a DRBD replication link between them. A work-in-progress
> writeup can be found at
> http://www.drbd.org/users-guide/s-pacemaker-floating-peers.html --
> please be patient; the information is still incomplete. It is set to be
> completed with the next maintenance release of the User's Guide, which
> is scheduled for shortly after the DRBD 8.3.3 release.
>
>> Now, the DRBD nodes are failing to sync. I am getting no obvious errors.
>> If I watch the /proc/drbd file, it goes through the motion of syncing,
>> and the progress bar briefly is seen. It then flips back.
>
> Probably just a result of the cluster manager detecting one cluster
> partition after another, as the underlying communication stack can't see
> its peer.
>
> Cheers,
> Florian
>
>
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