I have a 2 bay NAS, and I was planning on using 2x 18tb HDDs in raid 1. I was planning on purchasing 3 of these drives so when one fails I have the replacement. (I am aware that you should purchase at different times to reduce risk of them all failing at the same time)

Then I setup restic.

It makes backups so easy that I am wondering if I should even bother with raid.

Currently I have ~1TB of backups, and with restics snapshots, it won’t grow to be that big anyways.

Either way, I will be storing the backups in aws S3. So is it still worth it to use raid? (I also will be storing backups at my parents)

  • BakedCatboy@lemmy.mlEnglish
    3·
    10 days ago

    Keep in mind that if you set up raid using zfs or btrfs (idk how it works with other systems but that’s what I’ve used) then you also get scrubs which detect and fix bit rot and unrecoverable read errors. Without that or a similar system, those errors will go undetected and your backup system will backup those corrupted files as well.

    Personally one of the main reasons I used zfs and now btrfs with redundancy is to protect irreplaceable files (family memories and stuff) from those kinds of errors, as I used to just keep stuff on a hard drive until I discovered loads of my irreplaceable vacation photos to be corrupted, including the backups which backed up the corruption.

    If your files can be reacquired, then I don’t think it’s a big deal. But if they aren’t, then I think having scrubs or integrity checks with redundancy so that issues can be repaired, as well as backups with snapshots to prevent errors or mistakes from messing up your backups, is a necessity. But it just depends on how much you value your files.

    • Atemu@lemmy.mlEnglish
      31·
      10 days ago

      Note that you do not need any sort of redundancy to detect corruption.

      Redundancy only gains you the ability to have that corruption immediately and automatically repaired.

      While this sounds nice in theory, you have no use for such auto repair if you have backups handy because you can simply restore that data manually using your backups in the 2 times in your lifetime that such corruption actually occurs.
      (If you do not have backups handy, you should fix that before even thinking about RAID.)

      It’s incredibly costly to have such redundancy at a disk level and you’re almost always better off using those resources on more backups instead if data security is your primary concern.
      Downtime mitigation is another story but IMHO it’s hardly relevant for most home users.

      • Count042@lemmy.mlEnglish
        1·
        9 days ago

        backups in the 2 times in your lifetime that such corruption actually occurs.

        What are you even talking about here? This line invalidates everything else you’ve said.

        • Atemu@lemmy.mlEnglish
          1·
          9 days ago

          I was thinking whether I should elaborate on this when I wrote the previous reply.

          At the scale of most home users (~dozens of TiBs), corruption is actually quite unlikely to happen. It’ll happen maybe a handful of times in your lifetime if you’re unlucky.

          Disk failure is actually also not all that likely (maybe once every decade or so, maybe) but still quite a bit more likely than corruption.

          Just because it’s rare doesn’t mean it never happens or that you shouldn’t protect yourself against it though. You don’t want to be caught with your pants down when it does actually happen.

          My primary point is however that backups are sufficient to protect against this hazard and also protect you against quite a few other hazards. There are many other such hazards and a hard drive failing isn’t even the most likely among them (that’d be user error).
          If you care about data security first and foremost, you should therefore prioritise more backups over downtime mitigation technologies such as RAID.