ZFS is not magic - it needs backup and RAID

The Backup Wrap-Up

This one will get you talking! Jody Bruchon, author of “ZFS won’t save you: fancy filesystem fanatics need to get a clue about bit rot (and RAID-5),”, joins us on the podcast. The blog post went viral, resulting in three times as many words in the comments as the original article had. We start with an explanation of bit rot, why it happens, and why ZFS won’t be able to fix all bit rot. (For more information on bit rot, check out Episode 111 of this podcast here: https://www.backupcentral.com/tape-drive-designer-schools-mr-backup-on-tape-restore-it-all-podcast-111/). Jody then explains how ZFS needs disk redundancy in order for its self-healing features to work, and how if you don’t have that, you’re going to need backup to repair a ZFS volume damaged by bit rot. (We also talk about how it’s possible for a bit to be flipped without being noticed – even with ZFS.) Jody’s main concern is that people talk about how ZFS can be used to repair data corruption – without explaining how you need RAID-Z (or something) to use those features. He also explains why he prefers RAID-5 or RAID-10 to RAID-6. We then discuss “shucking,” the practice of buying external drives and ripping the drive out of them – to save money.

Curtis (Mr. Backup) then gets into an argument with Jody about the merits of Blu-Ray vs disk vs tape as a backup medium. Jody has some good points, but Curtis was unconvinced.

If you want to read Jody Bruchon’s original article, you can do so here: https://www.jodybruchon.com/2017/03/07/zfs-wont-save-you-fancy-filesystem-fanatics-need-to-get-a-clue-about-bit-rot-and-raid-5/