> From: Skylar Thompson [mailto:skylar.thomp...@gmail.com] > > I've been a TSM admin for years, so I admit I'm biased, but at scale I > don't think there is much competition to TSM. The advantage of the > progressive incremental backup (basically, incremental-forever w/o every > doing a full) outweighs the licensing costs.
This really gets at the heart of what I was thinking when I posted the question. When I'm asking you guys what you think about reliability, I'm asking if you have strong faith that these tools perform as designed, or if you think bugs etc, might cause failures with unexpected results. (Worse yet, undected failures.) It's understood, that if you were using "cp" or "tar" or basically any of these other tools for backup purposes, that you'd need to wrap it up with some kind of script or something. And if you want validation, you're creating and storing your own checksums, etc. When you have the incremental-forever (such as rdiff-backup) it seems to me, you have somewhat higher risk of data corruption than otherwise. But it's a good starting place, if you ensure the "current" image is the base standard, and you have to follow all the incrementals to go further back in time. It's definitely true, that recent backups get restored more frequently than old backups. I do believe zfs gets it right. The parent block contains the hash of all the children, and since the grandparent already validated the hash of the parent, you can safely assume the parent hash is correct. If a child hash doesn't match, the problem is the child, and not a corrupt hash stored in the parent. As Andrew said, end-to-end checksums is the way to go. _______________________________________________ Tech mailing list Tech@lists.lopsa.org https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
