[DRBD-user] migrating to a larger DRBD device

Lars Ellenberg Lars.Ellenberg at linbit.com
Mon Oct 11 12:16:08 CEST 2004

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

/ 2004-10-11 16:22:45 +1000
\ campbellm at cia.com.au:
> Hi,
> I have a question regarding migrating a DRBD device to a one of a
> different size (in this case, a larger partition), and do this without
> stopping any services.
> I have been experimenting with this and have found that, after resizing
> a device and then bring it up as a primary, it syncs and mounts the DRBD
> device ok, except that it creates it as the old size even though the
> lower level device on which it is mounted is much larger. 
> My guess is this is due to meta-data. Apart from maybe using a setup where
> the meta-data device is on a separate device, what would be the best way
> to do such a migration? One way might be to use 'tar' or 'cp' (maybe
> dump?) to backup up the existing DRBD device to somewhere else, and then 
> shut the machines down, create the new DRBD devices (either on a larger
> partition or a new disk), run drbdsetup, make the filesystem, and copy
> the data back.
> Is this pretty much the best way? I assume it cannot be done using the
> 'syncing' functions of DRBD, so that you could get away without having a
> service outage. Again, this assumes an 'internal' meta-data, although I
> guess that wouldn't make a difference anyway.

drbd is a block device, not a file system.
since drbd is a replicated block device, its announced size can not be
larger than the smallest replica.
since it is not the file system,
you need to resize the filesystem on top of it, too.

	Lars Ellenberg

please use the "List-Reply" function of your email client.

More information about the drbd-user mailing list