Time Machine on Ubuntu?

"I've used rsnapshot to excellent effect. You can have it rsync and keep as many old versions, based on time as you want/have space for. I've got 6 potential versions of things from today, daily for a week, 4 weeks, and then 6 months worth. I've already used it to recover several file I thought I'd lost due to overwriting.

The only problems I have had was it not running due to the previous run not completing in time, and so it left the lockfile dangling. This was on a remote machine that did password-less logins over SSH to rsync files off for backup/archive and I didn't log in very often to the server to check it. Running a logwatch script on there (emailing problems from the logs) at least made sure I saw the problems to restart it, and it's been hassle free ever since. On my local server, it's been no problem at all."

"Déjà Dup (day-ja-doop) is a simple backup program. It hides the complexity of doing backups the Right Way (encrypted, off-site, and regular) and uses duplicity as the backend.

Features:

Support for local or remote backup locations, including Amazon S3
Securely encrypts and compresses your data
Incrementally backs up, letting you restore from any particular backup
Schedules regular backups
Integrates well into your GNOME desktop"

I am not aware of TimeBachine directly but we use RSync with a scheduled cron job.

I for one am using Simple Backup Config/Restore, and backup the selected locations to an external hard-drive once every other day or so. Didn't have a problem as of yet, so I can't vouch for the restore part, but the backup one is OK.