In order to preseed a remote node with data which is then to be kept synchronized, and to skip the initial device synchronization, follow these steps.
This assumes that your local node has a configured, but disconnected
DRBD resource in the Primary role. That is to say, device
configuration is completed, identical drbd.conf
copies exist on both
nodes, and you have issued the commands for
initial resource promotion on your local node — but the remote node is not connected yet.
drbdadm new-current-uuid --clear-bitmap <resource>
dd
.
drbdadm new-current-uuid <resource>
Note the absence of the --clear-bitmap
option in this second
invocation.
drbdadm up resource
After the two peers connect, they will not initiate a full device
synchronization. Instead, the automatic synchronization that now
commences only covers those blocks that changed since the invocation
of drbdadm --clear-bitmap new-current-uuid
.
Even if there were no changes whatsoever since then, there may still be a brief synchronization period due to areas covered by the Activity Log being rolled back on the new Secondary. This may be mitigated by the use of checksum-based synchronization.
You may use this same procedure regardless of whether the resource is
a regular DRBD resource, or a stacked resource. For stacked resources,
simply add the -S
or --stacked
option to drbdadm
.