I’m done with RAID.
RAID comes in a variety of standard flavors , along with manufacturer-specific solutions (eg. X-RAID ). Most of the solutions are playing very fancy tricks with your data to gracefully handle hardware (disk) failure without data loss (the exception is RAID 0). Yes, disks can fail, and when they do you typically lose all the data, so designing a system to cope with this sounds like a great idea. The marketing behind these made-for-the-home RAID devices plays to your fears of suddenly losing all our data. They tell us we need their solution to avoid a nightmare.
What they don’t tell you is their advanced RAID system adds an additional layer between you and your data. A layer which is very complex and poorly implemented. I now believe that these RAID solutions, especially the recent explosion of home NAS devices, are less reliable than the drives they replace. Over the past 3 years I’ve been using RAID (ReadyNAS), I’ve had at least five software/firmware (the RAID controller) failures, with two falsely reported drive failures. Never did any of the drives (10 total) fail. Not once. I came close to losing data multiple times, always because of poorly written software, which I really didn’t need (since the disk drive didn’t fail).
They also don’t tell you that if their software fails badly (data corrupt/missing/etc), your only choice for data recovery is sending the whole unit to them. Only them. Doing any self data repair is nearly impossible, since each system has their own proprietary solution.
Yes, everyone should plan to avoid the nightmare of a drive going up in smoke, but the answer is almost never using a RAID solution. You only need to follow one simple principle: keep at least two physical copies of all your data. That’s it. Really. Want to be super-safe, physically secure one copy (a safe/offsite/etc).
I’ve recently replaced my ReadyNAS with a set of external drives. I copy all my data to multiple physical drives. If a drive fails, I have another copy (or two!) available. Simple.