DRBD tip
Thursday, January 13th, 2011I’ve been experimenting with DRBD, which looks great.
One thing confused me though: Resizing a DRBD device.
If the instructions on http://www.drbd.org/users-guide/s-resizing.html#s-growing-online are not working for you, and you get messages like this:
[ 1578.883204] block drbd0: Requested disk size is too big (19922944 > 10383360)
Try a reboot! The backing block device size as reported to DRBD may not update if you resize the backing device using LVM2.
For what it’s worth, this is the procedure I have now got for resizing a DRBD device. Obviously replace device names, sizes shown as appropriate.
- pvcreate /dev/sdb2
- vgextend drbdvg /dev/sdb2
- lvextend -L +11G /dev/drbdvg/lvol0 /dev/sdb2
- reboot!
- On boot, DRBD appeared to automagically resize my DRBD device: [ 8.342750] block drbd0: drbd_bm_resize called with capacity == 20766720
- Wait for sync to complete
- Resize the filesystem you have on your DRBD device, using e.g: resize2fs.
That is all.
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