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.)
So you have 56TB of total storage, but how much of that 56TB is actually used? Take the amount of storage used and add 10-12% to that figure. Now you create a new NAS (preferably off-site) with that amount of storage and that becomes your backup target. Take an initial backup (locally if possible to speed up the process) and then you can use something like rsync to create incremental backups going forward. This is the method I’ve used and so far it has worked out well. I target 10-12% more than the amount of used storage for my backup capacity because my storage use grows reasonably slowly. If your usage grows faster you might want to increase your “buffer” a little more so that you’re not having to constantly add drives to your backup target.
Yeah, this is certainly a viable “brute-force”-ish ooption. While I have 56, I’m only using 26 or so. But I’d actually be hesitant to do anything less than a full capacity mirror because I do expect to eventually use this (and more - adding drives to Unraid).
I’ve balked because of cost and upkeep (maintaining the same capacity, additional chances for drive failure, two separate sites I need physical access to with a high bandwidth connection), so I admit I was hoping I was missing an easier option.
I mean, if you want a full mirror, rolling your own backup target is going to be the cheapest option even with the current high price of hardware. Other options are cloud storage, or using another media like tape. Cloud storage is of course an on going cost which rules it out for me, not to mention privacy concerns. There are certain “cold storage” options from cloud storage hosts which are considerably cheaper but they have limitations on how the data can be accessed and how often. The tape route is possible but it’s not really viable for home use due to the high upfront cost of the drives. Outside of that, backing up a subset of your storage as others have suggested is the only other option. Creating viable backups without breaking the bank is a challenge as old as computers, unfortunately.