Dar has a lot of features (http://dar.linux.free.fr/doc/Features.html), but I don't see iterative backups listed- That's what's really useful about bup- I make daily snapshots of hundreds of VM images, and spend a LOT of disk space keeping past copies, just in case...
I generally keep complete copies from the past, since there's no easy way to say "Use this 20G image file as the base, then store the changes in this .iterativebkp file."
bup looks like a nice way to do that, but it'll need to mature a bit more (Like.. Pruning bkps..) before I could deploy it, even as a test system.
rdiff-backup (http://rdiff-backup.nongnu.org/) is very mature and efficient, using the rsync algorithm to store incrementals and save bandwidth. I use it for automated daily local/remote backups. I regularly use it to back up VMs. Restores are a snap. It has some nice features, like the ability to keep only N days of backups to save space for noncritical data.
I generally keep complete copies from the past, since there's no easy way to say "Use this 20G image file as the base, then store the changes in this .iterativebkp file."
bup looks like a nice way to do that, but it'll need to mature a bit more (Like.. Pruning bkps..) before I could deploy it, even as a test system.