I need to migrate an existing storage server running Debian 6, with many TB of data, to a HA setup. I can't simply shut down this server for any prolonged time (HA is required after all).
I plan to migrate this server to a DRBD cluster. I can't buy two new servers for this cluster; I need to reuse the existing server as a member of the cluster for cost reasons. Remember, I can't shut down anything for more than a few minutes at a time.
I have a new server ready, running Debian 8 to be the "master". I'd need to set up a "split brain" cluster using this "master" server; copy all data from the existing old server to the cluster; switch the existing services to the cluster; reconfigure the old server with Debian 8, then add it to the cluster as a "slave", resynchronize data, and at last have a redundant setup.
I've set up the cluster on the new machine, however, how to proceed? I can't even start the drbd service as the other "node" doesn't even exist yet...
I'm starting up from a previous drbd configuration that worked fine... with two available nodes.
Any help appreciated.