I don't know which specific Linux kernel FreeNAS is using, but it doesn't really matter: they all suck big time in fault-handling. The upcoming 2.6.21 kernel is the first one I'd really trust to do most things correctly, but even with that I have patches (my own) to fix obvious dead-in-the-head design relics in the SCSI layer (which is normally used for SATA drives).

So.. it's good, but about to get real for the first time. Hopefully by 2.6.23 or so, it should really kick saa.

EDIT: ahh.. FreeNAS is BSD -based?? Well.. that explains things a bit better..

Cheers