[DRBD-user] Problem with drbd and data alignment

Robert Altnoeder robert.altnoeder at linbit.com
Mon Mar 27 09:54:38 CEST 2017

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

The system looks for partition information at a certain offset on a
storage device. If DRBD is used to write directly to a raw storage
device, the effect of partitioning the DRBD device on the backing device
is the same as if the backing device had been partitioned directly with
no DRBD involved.
Therefore, the system will see the partition information on the backing

DRBD internal meta data is written to the end of the backing device
(without using any partitioning). The space occupied by the internal
meta data will be missing from the DRBD device's size (the DRBD device's
size will be the backing device's size minus the space reserved for
internal meta data).

On 03/25/2017 02:57 PM, Yannis Milios wrote:
> Not 100% sure but the first 'partition' could be where drbd stores
> metadata?
> Your setup should be fine as long ad you can deal in an easy manner
> with future resizing of the backing device (sde).
> Yannis
> root at iscsi2 ~]# lsblk
> ........
> sde 8:64 0 3,7T 0 disk
> ├─sde1 8:65 0 3,7T 0 part
> └─drbd2 147:2 0 3,7T 0 disk
> -- 
> Sent from Gmail Mobile
Robert Altnoeder
+43 1 817 82 92 0
robert.altnoeder at linbit.com

LINBIT | Keeping The Digital World Running
DRBD - Corosync - Pacemaker
f / t / in / g+

DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.

More information about the drbd-user mailing list