[DRBD-user] moving to a different backing device

Wayne Cuddy lists-drbd at useunix.net
Mon Feb 24 22:03:43 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.

On Thu, Feb 20, 2014 at 06:16:51PM +0100, Lionel Sausin wrote:
> Le 20/02/2014 18:08, Wayne a écrit :
> >Lionel,
> >
> >Thanks for the reply. Ok, I think I'll just start with the 'dd' route
> >and then do a resize once both systems are upgraded. So how does DRBD
> >keep track of the size of the backing device? Is that via the
> >/var/lib/drbd/drbd-minor-?.lkbd files?
> No idea, sorry - and that means I may just be plain wrong of course...
> >I have backups but a resync adds a lot of I/O load to the Primary
> >server which is a very busy DB server which is why I'm trying to avoid
> >a resync.
> Really, the dynamic sync speed is cool, it will only kick in when the 
> server is not busy.
> Of course that may mean very long sync times for you.
> >I'll start with the 'dd' method and if that works I'll report my
> >findings.
> >
> >Thanks again,
> My pleasure.
> Lionel.

For those who are interested, using 'dd' did work with one additional
step necessary. Note, I'm using DRBD 8.3 right now, not sure if this
is different for 8.4. 

-> drbdadm down $resource
- dd the source to the target backing device
- adjust drbd.conf to point to the new backing device for $resource
- the meta-data needs to be moved so drbd can find it
-> drbdmeta $drbd_device v08 $backing_device internal check-resize
- drbdadm up $resource

Replace $resource, $drbd_device and $backing_device with your local

The drbd device resync'd only what was necessary and I'm back in
business on the new RAID hardware.


More information about the drbd-user mailing list