Again Replication is currently not ready and no date has been set. To help others understand what DRBD is > DRBD is a block device which is designed to build high availability clusters. This is done by mirroring a whole block device via (a dedicated) network. You could see it as a network raid-1.

A short discription of how this will work when the 1.70 version is released. This is all the information that I will provide, as a later date will have more info on the subject.

Target Volume Replication:

iSCSI Target Volume Replication replication is very similar to RAID 1. The
first stage is rebuilding of the destination to be the copy of the source
volume. Next stage (endless) is online modifying the destination volume to
keep the mirror. The difference comparing to the RAID 1 is that, after any
broken connection only the changed data will be 'rebuild' (again first stage
takes place) on the destination.

Note: the replication should be performed on separate NIC and the
connection should be as fast as the main network connection, to prevent
lowering data throughput. Once you create the Target Volume you have the
choice to set it as
Source or Destination to the mirrored server. Replication of volumes should
be same size.

Changing destination to source without loosing data is only possible when
data is consistent.

How to change source to destination:
1. Stop replication task on source or turn off server
2. Now it will be possible to change destination to source, when the data is
consistent.