[Discuss] Backup linux desktops/workstations

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

On mac & windows, I'm accustomed to Time Machine and Acronis.  Key features
are:  
. Run in the background, low priority, no complaints from user about
performance.
. Daily (or more frequent) incrementals
. Able to specify excludes
. Able to restore whole system, or just a few individual files
. User doesn't need IT assistance to restore a few individual files

I'm willing to compromise on the last two points, and *maybe* even
compromise on the excludes.  But there can be no compromise on the first two
points.

I'm trying to find a suitable, similar backup solution for linux (ubuntu
desktop in particular).  Up till now, the best I've done is dump (ext4
filesystem.)  Unfortunately, even when I nice dump to the fullest extent,
it's still too resource intensive.  Users complain tremendously, as long as
it's running.

Any suggestions for alternatives?