DRBD was nice to use. Great thing about it is that you can put it below the existing filesystem. I don't remember how it works, maybe it puts metadata at the end of block device so filesystem should be shrinked before

I remember moving a huge NFS partition which was experiencing constant writes to another server with DRBD. With almost zero downtime. So is a nice tool if you want to move a filesystem with such huge amount of files that even iterating over the file tree takes hours

I was eyeing it pretty heavily recently, considering using it in my homelab for distributed ZFS. I wound up using Ceph since Proxmox has native support for it, but I still may try it out.

I’d like to be able to create zpools for DBs to take advantage of snapshotting, but combining ZFS and Ceph on the same underlying disk (even if they are enterprise NVMe drives) is fraught with peril.