[Discuss] Cloud-backup solutions for Linux?

[blu at nedharvey.com (Edward Ned Harvey (blu))]

> From: Bill Bogstad [mailto:bogstad at pobox.com]
> 
> > 2- Use a snapshotting filesystem like btrfs or zfs in the host, so the host can
> replicate the guest storage to another location seamlessly.
> 
> I don't see how this can work in a way that would be useful.
> Filesystem snapshots of your emulated disk images by the host OS may
> give you a single point in time copy, but they don't guarantee that
> the copy is in any way consistent. 

This is one of my favorite modes of operation. I run a ZFS host, and have guest VM's residing in zvol's, which get snapshotted and replicated periodically to additional attached storage, and offsite and offline.

If something happens, like the whole machine explodes or whatever, then I restore the guest snapshot, and power it on. The behavior of the guest machine is exactly as if the guest machine had been running and then suddenly the guest power was yanked or kernel panic or something. The guest storage device is a precise snapshot of what the guest storage would have looked like at the instant that the storage snapshot occurred.

If you're running an OS or some daemon that can't survive a power interruption, time to find a new OS or switch to a different daemon.