[DRBD-user] DRBD + LVM (GFS2)

[Graham Wood]

> I assumed this meant to create the drbd device first and create the LVM off
> of that.
One of the reasons I'm using LVM is to allow me to resize partitions.   
Changing the size of an LV is a lot easier than changing the size of a  
DRBD device (in my experience) - if nothing else.  It also means that  
you can have a single DRBD device split into as many LVs as you like  
(e.g. I've got mysql, apache, smaba, and asterisk on a 2 node cluster  
using a single DRBD device under it).

> However when I attempt the pvcreate I get the following error:
>   Device /dev/drbd0 not found (or ignored by filtering)
There are quite a few reasons for this.  The most likely (or at least  
the ones that I've hit myself in my build/testing):
- It's not in "primary" mode
- clvmd isn't running
- the machine's already seeing it as another name.

if you run "pvcreate -vvvv /dev/drbd0" and post the results (either on  
the list or direct, if it's deemed 'OT') - that should explain what's  
going on.

Given that you're going down the GFS2 route, have you got the rest of  
the Redhat Cluster stuff running?

Graham

(BTW:  I've got the cluster running, but get kernel oops as soon as I  
try to use GFS/GFS2, so I'm interested in feedback about it working on  
DRBD)