Remote, automated, secure backups is the most difficult and time-consuming Gentoo project I've undertaken.
Right now I'm pushing data from each of my systems to a backup server via rdiff-backup. The main problem with this is if a system is compromised its backup is also vulnerable. Also, you can't restrict rdiff-backup to a particular directory in authorized_keys like you can with rsync, and rdiff-backup isn't very good over the internet (I've had trouble on sub-optimal connections) and it's recommended on the mailing list to use rdiff-backup either before or after rsync'ing over the internet. We've discussed this vulnerability here before and it was suggested that I use hard links to version the rdiff-backup repository on the backup server in case it's tampered with. I've been studying hard links, cp -al, rsnapshot (which uses rsync and hard links), and rsync --link-dest (which uses hard links) but I can't figure out how that would work without the inevitable duplication of data on a large scale. Can anyone think of an automated method that remotely and securely backs up data from one system to another, preserves permissions and ownership, and keeps the backups safe even if the backed-up system is compromised? I did delve into bacula but decided it was overkill for just a few systems. - Grant
