… could destroy the original master too”, however, is plain false. DRBD won’t “destroy the original master” any more than… you want with a database that you run off a DRBD LVM snapshot. Works on a Secondary node too. I’m not sure… replication is however something quite helpful for some environments. Though DRBD also could be extended to support one if needed. Now…

… an lvm snapshot of the DRBD secondary node. Surely you can. If DRBD sits on top of LVM, then you snapshot the LVM and you get a snapshot of the blocks on the drbd device. Whether DRBD is…, I will leave with this note – we actually do both – drbd + ha cluster for high-availability and a big beefy slave…

…. I would add another point: Backup from slave / secondary. With DRBD this is hard / impossible in many situations. We use both, replication and DRBD in production. One database which is doing nothing but “spooling… using DRBD here too but did not do it because we’d loose the ability to do “online schema change” or LVM snapshot…