[DRBD-user] Please help... After reboot I'm always getting unresolved split brain (DRBD+OCFS2)

Felix Frank ff at mpexnet.de
Fri Jan 25 00:14:08 CET 2013


Hi,

On 01/24/2013 06:04 PM, Jacek Osiecki wrote:
>
> umount: /dev/drbd0: not mounted
> all: Failure: (127) Device minor not allocated
> ERROR: Module drbd is in use
> .

That looks very weird. I don't quite remember how to cleanly unmount an 
ocfs2. Make sure you can start and stop both the FS and DRBD while 
running. If you got that figured out, apply that to your boot sequence.

> Any ideas? Am I getting it right that if drbd would stop well before
> network shutdown, the node would reconnect as primary-primary after reboot?

Absolutely. Of course, mounting ocfs2 must not happen until the drbd 
connection is established and the local node promoted. (More 
specifically - make sure your local node does not promote itself before 
it's connected.)

> It's so in my linux distro... I got much newer kernel but seems that
> still it's only 8.3 drbd in it.

You should build your own userland (package) then, although even that is 
not always trivial.

> I'm using it for a HA configuration, where two machines are serving the
> same data through WWW server. Machines are set behind a load balancer.
> It would be nice if after rebooting any node, it would refresh its data
> from the other node and then start serving data as usual...

That's what happens, but honestly - this is not exactly a high speed 
setup. Have you done benchmarks? Gluster might be a more appropriate 
solution, even though the consistency is probably better with ocfs/drbd.

I notice you chose to ignore my most pressing point: stonith is 
mandatory for dual-primary operation. Do you have a good reason to not 
use pacemaker?

Cheers,
Felix



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