[DRBD-user] Resize external md

Christian Völker knebb at knebb.de
Sat Dec 20 20:59:09 CET 2014

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


I do not exactly know what you are talking about ;-)

So you have a drbd device which need to grow, right? On one server (or
on both?)  the disk (lv) for the drbd device is a LVM logical volume,
And I guess you are talking of the PE size of the volume group which is
configured for 32MB resulting in a max LV size of 1TB?

First, with LVM2 there is no such limit any more. Check your LVM version
with "lvm version".
Second, even 32MB PE size should be ok for 2TB LVs.

In both cases it is out of scope for drbd as drbd just uses what it
gets. So look for a way to extend you underlying LVs and then extend
drbd according to the docs (drbd adjust).

In case you can not extend your underlying devices (for whatever reason)
you might go the risky way and detach the device from drbd (so it has
only one out of two disks). drbd will continue to run. Delete the old
device and create a new one with the desired size. Attach it then. drbd
will sync the data to the new device. After sync is done do the same
with the second node. And then drbdadm adjust.

However, backup is strongly suggested!

Good luck!


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