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)

  • AtemuEnglish
    1·
    17 hours ago

    if it’s a 1:1 full disk image, then there’s almost no difference with the costs of raid1

    The problem with that statement is that you’re likening a redundant but dependant copy to a backup which is a redundant independent copy. RAID is not a backup.

    As an easy example to illustrate this point: if you delete all of your files, they will still be present in a backup while RAID will happily delete the data on all drives at the same time.

    Additionally, backup tools such as restic offer compression and deduplication which saves quite a bit of space; allowing you to store multiple revisions of your data while requiring less space than the original data in most cases.

    In this case he’s talking about restic, which can restore data but very hard to do a full bootable linux system - stuff needs to be reinstalled

    It’s totally possible to make a backup of the root filesystem tree and restore a full system from that if you know what you’re doing. It’s not even that hard: Format disks, extract backup, adjust fstab, reinstall bootloader, kernels and initrd into the boot/ESP partition(s).

    There’s also the wasteful but dead simple method to backing up your whole system with all its configuration which is full-disk backups. The only thing this will not back up are EFI vars but those are easy to simply set again or would just remain set as long as you don’t switch motherboards.

    I’m used to Borgbackup which fulfils a very similar purpose to restic, so I didn’t know this but restic doesn’t appear to have first-class support for backing up whole block devices but it appears this can be made to work too: https://github.com/restic/restic/issues/949

    I must admit that I also didn’t think of this as a huge issue because declarative system configuration is a thing. If you’re used to it, you have a very different view on the importance of system configuration state.
    If my server died, it’d be a few minutes of setting up the disk format and then waiting for a ~3.5GiB download after which everything would work exactly as it did before modulo user data. (The disk format step could also be automatic but I didn’t bother implementing that yet because of https://xkcd.com/1205/.)