I have a 56 TB local Unraid NAS that is parity protected against single drive failure, and while I think a single drive failing and being parity recovered covers data loss 95% of the time, I’m always concerned about two drives failing or a site-/system-wide disaster that takes out the whole NAS.
For other larger local hosters who are smarter and more prepared, what do you do? Do you sync it off site? How do you deal with cost and bandwidth needs if so? What other backup strategies do you use?
(Sorry if this standard scenario has been discussed - searching didn’t turn up anything.)


I’m not sure if I qualify as a ‘larger local hoster’ but I would go through your 20 TB and decide what really is important enough to backup in case the wheels fall off. Linux ISOs, those can be re-downloaded, although it would take a bit of time. The things that can’t be readily downloaded such as my music collection that I have been accumulating for decades, converted to flac, and meticulously tagged, can’t be re-downloaded. So that is one of my priorities to back up. Pictures, business documents, personal documents, can’t be re-downloaded, so that goes on the ‘must back up’ list…and so on. Just cull out what is and isn’t replaceable. I would bet that once you do that, your 20 TB will be a bit more slim, and you’re not trying to push 20TB up the pipe to a cloud backup.
I use BackBlaze’s Personal, unlimited tier for $99 USD per year, which is a pretty sweet deal. One thing about Backblaze to remember is that the drives being backed up must be physically connected to the PC doing the backup/uploading. I get around that because I have a hot swap bay on my main PC, but there are other methods and software that will masquerade your NAS or other as a physically connected drive.
Backblaze personal doesn’t support Linux or BSD, so it would be useless for a NAS.
I use backblaze too, started with the personal back up, but swapped to the B2 solution as it was supported by my NAS. The cost of the actual storage isn’t much, most of the cost is in access, so for data that doesn’t alter much it worked out just as cheap, and easier to do things that way.
The cost of B2 storage is very high, what are you talking about? USD$6 per terabyte per month would be like $4k a year for me.
I’m cheap and my labor is free. LOL But you do have a point.