Yeah. There's no decent replacement for ZFS. I use ZFS + KVM + Sanoid + Borg(matic) + Borgbase. With the native encryption and TRIM support added to ZFS in 0.8 there isn't anything close in terms of ease of use.

Linus seems out of touch on this one IMHO.

XFS on LVM thin pool thin LV gives you fas CoW snapshots and is rock solid. Really, try it. :)

I don't remember the details, but when I looked into switching to LVM snapshots, I ran into some sort of blocker.

My use-case is that I run Sandstorm, and want to be able to back it up while it's running. That means:

  - Ensure there aren't any existing snapshots
  - Take a snapshot
  - Mount the snapshot as a filesystem
  - Run tarsnap against that filesystem
  - Release the snapshot

I think the trouble I ran into was at the mount step.

in the application-level, snapshotting is not a way to do "consistent backup"s . consistent backup is a backup with a planned or known state when "restore"ing.

Sure it is. Quiesce your application, take a snapshot, then resume application. Then you can back up the snapshot. The alternative can be a lengthy downtime for your application.

I can't do anything about partial file writes in the general case, but it's close enough—and any ACID databases should be able to restore from such a snapshot.

LVM snapshots has been good enough for consistent backups for the last 20 years. Then there is also thin snapshots if you feel fancy.