Make sure you're snapshotting with exponential-style backoff (e.g. keep 24 hours of hourly snapshots, 7 days of daily snapshots, a few weeks of weekly snapshots

Make sure you're snapshotting with exponential-style backoff (e.g. keep 24 hours of hourly snapshots, 7 days of daily snapshots, a few weeks of weekly snapshots, etc.) to guard against clobbering or deleting data. ZFS isn't an absolute panacea. It can get very confused if you have a systematic problem one day - e.g. if you ever have intermittent bus problems (e.g. dodgy backplane), it can start to believe that that blocks are permanently damaged and it's hard to convince it to read through to the disk storage. I had to copy the superblock from an old snapshot[1] once because it was convinced all of its copies were bad. This wasn't during writes; it was during a zfs scrub. If you don't do it regularly, act like a zfs scrub could potentially wipe out all your data. This is more likely on home hardware, without ECC RAM and less likely to be built to handle loads of concurrent I/O throughput. Keep on using backups. [1] Thankfully, because of my snapshotting policy, my old snapshot wasn't actually very old.