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by hammyhavoc 324 days ago
If you have a redundant dataset (#1 reason to use ZFS replication) then you can repair a ZFS dataset.
2 comments

Hit the comment depth limit (so annoying), but the comment about repairing blocks means that you can repair bitrot/corruption/malicious changes/whatever down to the block level of a ZFS dataset if you have a redundant replicated dataset.

The magic of ZFS repairs isn't in RAID itself, IMO, it's in being able to take your cold replicated dataset, e.g., from LTO, an external disk, remote server etc, and repair any issues without needing to resilver, stress the whole array, interrupt access, or hurt performance.

RAID can correct issues, yes, but ZFS as a filesystem can repair itself from redundant datasets. Likewise, you can mount the snapshots like Apple Time Machine and get back specific versions of individual files.

I wish HN didn't limit comment depth as these are great questions and this is heavily under-discussed, but it's arguably the best reason to run ZFS, IMO.

Another way of putting this—you don't need a RAID array, you can do individual ZFS disks and still replicate and repair them. There's no limits to how many replicas or mediums you use either. It's quite amazing for self-healing problems with your datasets.

The rate limiter is only applied to accounts that post too many comments that are of low-quality or break the guidelines. We're always open to turning off the rate limiter on an account but we need to see that the user has shown a sincere intent to use HN as intended over a reasonable period of time.
I've been using HN since 2018, and whilst I'm a bit rough around the edges, I generally interact with the best of intentions as long as my blood glucose is within range (which, with a CGM, is more than at any other point in my life).
> Hit the comment depth limit (so annoying)

I think it’s actually a flamewar detector that you may be hitting. In any case, next time try selecting the timestamp of the comment which you wish to reply to; this works when the reply button is missing and the comment isn’t [dead] or [flagged][dead] iirc.

Thanks!
I'm sorry, I still don't quite follow... If you have a RAID5, you can repair a drive failure... Weren't we talking about handling 'blocks'? Is it bad blocks or bad block devices (a.k.a. dead drives)?