Stoic, one of the things you seem to be implying above is that RAID can be a stand-in for backup (the comment about how do you backup 10TB of data). As far as I understand that's contrary to common wisdom about RAID.-JavaJones
Many of the really high-end deduplicating RAID6 storage devices claim to be able to eliminate the need for a backup. However I'm not entirely sold on that idea either. I prefer to have RAID as a first line of defense, and then have a backup for those "special moments" when shit really hits the fan.
Here's the thing, from SMBs to SOHOs down to the average Home Owner, everybody is on-a-budget. So what typically happens is enough hardware is bought to store the data being used. Some type of backup is discussed and is maybe even used a few times. Then the data grows and the space needed to store it gets bigger. Now it all no-longer fits on the backup, so the "important stuff" discussion ensues. Either that or somebody comes up with the "Let's do an incremental backup" idea, and nobody has the forethought to shoot them for saying it ... before the plan is put in place.
Note: I'm cringing right now just thinking about the number of time I walked into a new client to find they've been using the same five pieces of media to do incremental backups, for the last five years ... Chance of a successful recovery? Zero!
Both scenarios tend to end badly as backups just love to fail. And they do so at an extremely high rate. RAID on the other hand, could fail. Synchronization & backup schemes both have the same (glaring) flaw. The are simple, easy, set-it-and-
forget-it systems. ...and it's that last,
forget it, part that bites'em in the ass every time!
Synchronization, like mirroring (RAID1) both like to give people two identical copies of the same error. So if a disk fails in the middle of a sync... (point here being every system has a weak point)
Now for the average end user that comes trotting home with a brand new PC, a few ideas of what they can do with it, and maybe even a shiny new digital camera... Obviously a server would be a completely stupid to even suggest. (I'm picturing Goofy from the old Disney driving cartoons trotting out of a BestBuy here)
However, you and SB are not typical end users. You have an established system architected into a strategy that is so far working for you. Great go with it. SB on the other hand, is looking to start-from-scratch (so to speak), and is coming out of the gate planing on warehousing 10+TB of data. Those NAS boxes ain't cheap, as anything with more than 2-3 slots is well over $1,000. So if you looking at budgeting enough money for three of those ... You are much better off going with the off-lease commercial hardware that will give you a true scale-able hardware RAID configuration for a fraction of the money you would have spent on the consumer grade stuff.
Even if you are working out of your mother's basement (not saying you guys are), with 10+TB of data you have an enterprise class problem ... Which should be handled in much the same way regardless of where the data is and whom it belongs.
I'm hoping I covered everything as this has takes awhile for me to type.
