[DRBD-user] LVM + DRBD + XFS and resize

[Rois Cannon]

DRBD 8.0.6 / HEARTBEAT 2.0.8-4

I'm having some problems resizing and I'm sure what I've done wrong will
be obvious to someone.  

I have XFS filesystem on top of a drbd, on top of an LVM.  To expand I'm
doing 'lvextend /dev/vg0/home -L +128M' and 'drbdadm adjust home' on
both nodes first.  Once that's done I'm doing xfs_grow /dev/drbd0 on the
primary node only.  It seemed to work the first time but just to make
sure I did it a couple more times and it breaks drbd0.  df isn't showing
the increased size and if I restart drbd it won't come up and gives this
message:

Failure: (119) No valid meta-data signature found.

        ==> Use 'drbdadm create-md res' to initialize meta-data area.
<==

Command 'drbdsetup /dev/drbd0 disk /dev/vg0/home /dev/vg0/home internal
--set-defaults --create-device --fencing=resource-only
--on-io-error=detach' terminated with exit code 10

I put the meta data on a separate lvm and that seems to keep the meta
data from having problems but before I can grow the xfs filesystem I
have to restart the cluster to get the drbd to re-sync?

(ON BOTH NODES)
lvextend /dev/vg0/home -L +128M
drbdadm adjust home
heartbeat stop
drbd stop
drbd start
heartbeat start

(ON THE PRIMARY ONLY)
xfs_grow /dev/drbd0

Does this sound correct or is there a way to get drbd0 to re-sync
without restarting the whole cluster?  It only took 30 seconds for the
cluster to restart but I'd rather not have to interrupt users in the
middle of the day if I need to expand some space.

Can anyone point me to some docs on this?