In my setup I have two machines. Both of them have almost the same setup, except for the amount of RAM. On both sides I want to designate /dev/sdb1 as the underlying device for a common /dev/drbd0.
As I understand it (please correct me if I'm wrong) primary-to-primary is the way to go when I want to be able to write to the resulting /dev/drbd0 from both machines. However, performance is not my biggest concern here. The important thing is that no extra effort (such as rsync) is required to keep them in sync.
Now, reading the documentation I got confused as to whether a clustering file system (such as GFS) goes on top of that device or has to be (somehow?!) layered underneath the /dev/drbd0. Can someone shed light on that?
I'd also like to know what solution is generally preferred for such a scenario.
NB: If you can recommend alternatives to DRBD, feel free to name them and provide pointers.
You would need to format that device with a filesystem that is cluster aware and one that uses a distributed lock manager (such as GFS.) So GFS would be on top of the drbd device.