Actually, FlexRAID is a quite funny little beast, since it can protect folders too, instead of drives. For (windows) example you might want to protect your drive D and E and only your "Music" folder from drive F.
Or in my case, I have mounted my media storage drives (12 drives) to folders like this:
- C:\Pool\PPU-01 (used as a parity)
I have pooled those 12 drives to one big drive (as a drive P: / 20 TB) so I don't have to worry which one of my drives has enough space left for my data. Now, if for some reason I decide NOT to use FlexRAID anymore, all my data is still available, since FlexRAID doesn't touch my original data.
FlexRAID isn't perfect for everyone, but for me it is. I didn't want to build another box for storage only. Now my W2008R2 frankenserver has many roles: NAS / XBMC / DVB-T PVR (4 tuners) / VMWare Workstation host (Ubuntu Server without gui and WHS v1 for client backups) / AD+DNS+DCHP ...
I needed something that sits on top of existing filesystem and FlexRAID is just the right poison for me. If my W2008R2 for some reason dies, all my "FlexRAID protected" data is still readable and after new OS install I can just reinstall FlexRAID, recalculate parity and pool my drives again.This is quite neat, in my opinion.
But I am still looking closely what Microsoft's new and upcoming Storage Spaces (parity mode) brings to the table. Deduplication? I don't know how useful that is with media files. Waiting for "Server 8" and some reviews first...