[DRBD-user] DRBD - one half of Proxmox cluster miscommunicating

James Gibbon james.gibbon at virgin.net
Tue Jul 31 15:23:33 CEST 2012

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Tue, 31 Jul 2012 15:03:22 +0200
Felix Frank <ff at mpexnet.de> wrote:

> On 07/31/2012 02:49 PM, James Gibbon wrote:
> > Can someone tell me what the "become-primary-on-both" part
> > means? I'm fairly anxious to ensure that the second node
> > doesn't attempt to become primary when its restarted as its
> > data will be out of date..
> It does what you assume. The initscript will promote either
> node upon booting. This will cause split brain if connection
> isn't established first. Please note that there are other ways
> to start DRBD besides the initscript, notably pacemaker.

OK - thanks again. Since the master is already up and running,
I'm hoping that the broken secondary box isn't going to get
promoted - is that a reasonable assumption?

Sorry if I'm being anally careful about this. The consequences
of losing the current sane view of the data would be quite serious

> I only just noticed this: You do have a dual-primary setup. I
> shall assume this is for live migration purposes and/or mixing
> active LVs among peers (i.e. in one VG, each peer has a couple
> of active LVs. I believe you need cLVM for that).

Yes, it is possible to migrate a VM from one server to the other
while it's running - a very nice feature.

So given that it's a dual primary setup, is the strategy of doing

1. fix network config on server2 and reboot it
2. server2 # drbdadm disconnect all
3. server2 # drbdadm secondary all
4. server2 # drbadm connect --discard-my-data all

Still going to work?

Thanks ..

James Gibbon <james.gibbon at virgin.net>

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