System image backup?

[Linux for blind general discussion]

I use partimage for this purpose, but it does have a few limitations:

1. The partition you're backing up or restoring has to be unmounted,
so it can't be used on the root partition of a running system. I get
around this by running partimage from a LiveDVD, though the
inconvenience of booting into the live environment to make backups
means I don't make backups as often as I should.

2. As far as I know, Partimage's operation is all or nothing. Creating
a new backup copies everything from the target partition and there are
no incremental backups, restoring a backup erases everything on the
partition. For this reasons, I try to keep how much I have on my root
partition as low as possible and have to remind myself to copy the
contents of my home directory prior to restoring a backup.

3. As far as I know, partimage doesn't support ext4. My own system
runs on ReiserFS, but I understand ext4 is a very common filesystem
these days.

On the upside, Partimage only copies the files instead of every
individual block, so it's much faster than dd, produces much smaler
uncompress images, and can compress the images it makes directly.