Synchronizing the database isn't quite what you want. It's true that in the case of an errant rm -rf it would almost certainly have helped, but it's approximately as easy to run a "DELETE FROM importantdata" and leave off the "WHERE" clause, which would get replicated. And certainly if you're using DRBD (replicate the volume, not the database), an rm -rf will get replicated.
I'm just genuinely unsure what a better outcome would have been here. (It's certainly a process failure that no backups existed other than the manual 6-hour-old snapshot, but I'm not sure you can do much better than automating that.)
You can easily add snapshotting using on-disk technologies like LVM or ZFS to that and achieve reliability against such an issue though, as well as being able to do a full text backup (ie: to SQL) from your replicated server at higher performance than you would on production.
They had LVM snapshots every 24 hours. They lost 6 hours of data because someone had coincidentally triggered a snapshot 6 hours prior to the deletion event. Otherwise, they would've lost several more hours of data.
I'm just genuinely unsure what a better outcome would have been here. (It's certainly a process failure that no backups existed other than the manual 6-hour-old snapshot, but I'm not sure you can do much better than automating that.)