[DRBD-user] Split brain in a dual primary configuration

Jean-Francois Chevrette jfchevrette at iweb.com
Fri Oct 30 20:14:28 CET 2009

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


On 09-10-30 3:07 PM, Gianluca Cecchi wrote:
> Hello,
> the message is self explanatory: in drbd.conf you define the policy to
> "disconnect" when you get a split brain (sb) deriving from a 2-primary
> scenario.
> And so does drbd...

But what else would be more appropriate for such a situation? In fact, 
that's what we want to do, have both nodes to disconnect. We don't want 
either of them to become secondary.

Is it acceptable to have both nodes remain primaries while they are 
disconnected and expect them to sync to each other properly when they 
are connected again?

> btw: having you dual primary and LVM, are you using also CLVMD?
> Otherwise if you do modifications on one VG (such as add an lv) you
> don't see them immediately, because you don't have cluster locking...

We are not using clvm. When a new VG or LV is created, we see it 
immediately on the second node. Maybe Citrix XenServer has a mechanism 
so that LVM is reloaded on both nodes when a new VM is created on the 

Jean-François Chevrette [iWeb]

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