[linux-lvm] LVM1 on top of DRBD

[Joachim Banzhaf]

Hi list,

I'd like to use LVM1 on top of DRBD 0.6.6 and not the other way round, because 
I then can resize my partitions online (add a new drbd device, make it a pv, 
add it to a vg, be happy).

It just seems not to be that simple.

The HOWTO warns about LVM not being cluster aware and describes how to do it 
anyway on shared storage. I (think I) have these requirements met by using 
heartbeat to have vg's active at one node only and running vgscan on the 
secondary after changes on the primary. 

I created the pv's using the /dev/nbx devices (x=1,2).
I created the vg lvm-drbd with lv lv1-s2 using these pv's.

The corresponding haresources file is this:
job-vm1 192.168.1.101 datadisk::lvm1 datadisk::lvm2 LVM::lvm-drbd \
  Filesystem::/dev/lvm-drbd/lv1-s2::/ha/export::reiserfs

What I get is lvm using the lower level device (sdbx in my case).
vgdisplay -vD shows the pv's using /dev/sdbx.
Nothing gets replicated to the other node (not surprising then).
I even patched lvm_check_dev.c and rebuilt the lvm tools to ignore /dev/sdbx 
devices, removed all lvm infos from /etc and did a new vgscan and 
vgcfgbackup. vgdisplay -vD now shows the /dev/nbx devices for the pv's.
But still no replication without drbdsetup /dev/nbx replicate :-(.

I use suse 8.2 with suse 2.4.20-4GB kernel (you'ed a few weeks ago)
for the lvm_check_dev.c-patch I installed the lvm source rpm, modified the 
spec file not to use the mp patches (because a file was missing), added my 
patchfile and did a rpm -bi /usr/src/packages/SPECS/lvm.spec.

Btw. the build process did not stop on compile errors in lvm_check_dev.c. Is 
that intended? It is confusing...

What am I doing wrong?
Is it possible doing LVM on top of DRBD at all?

I'd happily provide more details if it helps.

Ciao,

Joachim Banzhaf