[DRBD-user] Help: Replacing A Dead Node

Mike Sweetser - Adhost mikesw at adhost.com
Mon Jul 28 23:31:49 CEST 2008

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


> it is now StandAlone Secondary Inconsistent.
> since an Inconsistent device cannot become SyncSource
> (and a Primary device will refuse to become SyncTarget)
> just make sure your good data is Primary still,
> and say "drbdadm adjust all" now.

So basically, as long as I'm sure that the good data is Primary (which
it should be under Heartbeat) then doing "drbdadm adjust all" will
reconnect the two DRBDs and begin the resync process?  Am I on target
there?

> you probably should not start the cluster manager yet, though, unless
> you are sure that your sedtup knows how to deal with a degraded drbd.

Right, Heartbeat's staying off on the new node until the
resynchronization is completed - it will only be running for now on the
Primary node.

> if you did not make it Primary, and there is no cluster manager,
> and you just created fresh meta data that marks it as Inconsistent,
> there is no way it possibly could be Primary...

I figured as much, but considering there's a good amount of work
involved in trying to redo this if I get it wrong, I just wanted to make
100% sure. :)

So my new plan would be:

* Reinit the metadata on the new node (new: drbdadm create-md all)
* Attach the nodes (new: drbdadm attach all)
* Verify that the new node is StandAlone and Secondary/Inconsistent
* Verify that the original node is Primary
* Run the adjust on the new node (new and possibly old: drbdadm adjust
all)

Is that about right?

> you can keep heartbeat running on the "Primary", no problem.
> but while it is possible to configure heartbeat + drbd to behave
nicely
> even while drbd is degraded, it is easy to get it wrong.
> I'd recommend to keep heartbeat off
> on the newly to be integrated node, until it is ready.

Yup, that's the plan.  I'm going to keep Heartbeat running ONLY on the
original node for now until the resync is completed.  Then I'll get
Heartbeat functional again and get everything happy.

Mike Sweetser



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