RAID isn't a backup. Anybody who says otherwise has no idea what they're talking about, or is trying to sell you something.
RAID can be part of a high-availability setup designed to avoid needing to access your backups, but it is not by itself a backup.
Now, as far as what's best for your use case, it's hard to say without a lot more detail, but based on what you have stated, you have two options if you want local storage that will keep working if one of the storage devices fail:
- Buy two bigger drives, and just migrate your existing array to those. This is simple, and probably the least likely to break. It does however put an upper bound on how much space you can use (because it's not likely you'll be buying anything bigger than 8TB). If you take this approach, you probably want to avoid SMR drives and get regular ones.
- Buy a couple more 3TB drives, and convert everything to RAID5 or RAID6. This will give you better storage capacity, still survive one or two drives failing respectively, and may actually give you much better read performance.
As far as actual backups, just pay for a second cloud storage site (or if you're being sensible and using something like Amazon S3 that lets you specify location, set up a second storage location and back up to both).
2Well first of all, RAID is not a backup solution. Also striped disks have 0 redundancy. Ultimately though whatever is adequate is up to you – Eric F – 2018-05-25T18:00:44.800
2Why would you go from RAID 1 to RAID 1? You lose the single disk redundancy you currently have. A good backup rule is to have three copies. The first is the original, the second is a local backup (I.e. NAS), the third shouldn’t be in the same location has either of those. Cloud storage is cheap, the more copies, the better – Ramhound – 2018-05-25T18:06:29.990
All tho Raid 1 is better, it is not a good backup solution but that being said Raid 1 stores the same data on 2 separate drives, if one drive fails you still have your data on the other drive, but if the data gets corrupted or malware encrypts it both drives data is toast.You are Best to have at least 3 different backups, 2 locally and one in the cloud. As said earlier Raid 0 has absolutely no redundancy and is for performance only. – Moab – 2018-05-25T19:48:19.773
Those are also my thoughts. Trying to think of a cheap way to get this to work. I guess I can always take a cold storage bluray backup for archives. Active data should only be there as a backup anyway. DLNA items aren't too big of a concern if lost. These pictures and videos will be put on archive media as well. So as painful as it is to spend 12 hours burning and verifying a BD-R disk, it may be the only reasonable option that is cheap. Online storage may be "cheap" but not in my eyes xD. Especially pay by the gig services when you need to recover your data -_- – naps1saps – 2018-05-26T08:31:03.790