I am mainly hosting Jellyfin, Nextcloud, and Audiobookself. The files for these services are currently stored on a 2TB HDD and I don’t want to lose them in case of a drive failure. I bought two 12TB HDDs because 2TB got tight and I thought I could add redundancy to my system, to prevent data loss due to a drive failure. I thought I would go with a RAID 2 (or another form of RAID?), but everyone on the internet says that RAID is not a backup. I am not sure if I need a backup. I just want to avoid losing my files when the disk fails.
How should I proceed? Should I use RAID2, or rsync the files every, let’s say, week? I don’t want to have another machine, so I would hook up the rsync target drive to the same machine as the rsync host drive! Rsyncing the files seems to be very cumbersome (also when using a cron job).
Everyone repeat with me: RAID IS NOT BACKUP.
Never was, never will be.
Raid can protect you from a single drive failure in case you need an “always on” setup. Even then, if the drives are identical, they can fail within days from each other. If you don’t have monitoring, you’ll lose everything before you can react. I feel that’s not your use case.
You need backup. You can use something like rsync or even better borg backup. Keep the backup offline and backup often. You’ll be safer that way.
2 disks in the same machine is not a backup whether the data is copied between them using RAID or rsync or anything else.
Sounds like for this machine, just use the two disks in RAID1, or a ZFS mirror, or something. And figure out something else for backups. Probably a cloud solution.
Also, RAID2 requires a minimum of 3 disks, and is rarely used.
I’d argue it is a backup as long as something is doing snapshots of some kind to the other disk, and not realtime sync like raid. Obviously that should not be your only backup though.
RAID is redundancy, not backup. The main purpose is to keep your system available while you deal with certain, specific types of failures. Also, for all intents and purposes, RAID2 isn’t a thing. I suspect you were reading about RAIDZ, RAID using ZFS. While it has proponents and advantages, it won’t secure your data any more than the common RAID5/6.
Backup is to make sure you don’t lose data, regardless of what happened. This includes hardware failures, user error, bad/malicious software, and more.
If your data is important to you, setup a backup. If you need 100% uptime, setup a backup, then setup RAID.
everyone on the internet says that RAID is not a backup
Because it is not.
I just want to avoid losing my files when the disk fails.
Backups. Preferably multiple. At least one of them off site.
I would hook up the rsync target drive to the same machine as the rsync host drive
And lose both in case there’s a power supply failure, voltage spike on the grid, water spill or something else. Plenty of options which will fry the whole system.
