We have sensor units scattered across a couple square miles of undeveloped land, which each collect ~500 gigs of data per 24h. When these drives come back from the field each day, they'll be plugged into a server featuring a dozen removable drive sleds. We need to present the contents of these drives as one unified tree (shared out via samba), and the best way to go about that appears to be a unioning file system. There's also requirement that the server has to boot in 30 seconds or less off a mechanical hard drive.
We've been looking around, but are having trouble finding info for this seemingly simple situation. Can we get FreeNAS to do this? Do we try Greyhole? Is there a distro that can run unionfs/aufs/mhddfs out-of-the-box without messing with manual recompiling? Why is documentation for *nix always so bad?
(posting as AC due to silly workplace security policies)