One thing I forgot to mention in my post about newthe is that I had a play with SATA hotswap while testing it.
I'd ordered the second drive separately, as it worked out a lot
cheaper. The main machine arrived first so I configured it up and when
the new drive arrived I pulled a spare drive caddy, screwed the drive
into it and slotted the drive into the machine. And then wondered how to
get it detected (I've memories of rescan-scsi-bus for SCSI drives). I
didn't find anything conclusive, so I had a prod around. And eventually
realised that it had Just Worked without any action on my part - the
/dev/sdb device node had been created and I could setup the new
drive and add it to the RAID array. Nice. Pulling the drive also got
detected fine - on a reinsertion it became
sdc but that's not an
issue as I have MD and LVM sitting on top so raw device nodes don't
matter so much.
This is with the
ahci driver on an Intel ICH7 chipset FWIW. And the
decision for software RAID was a conscious one; I've seen drives fail
more than once under RAID1/MD and get correctly kicked out of the array
while the machine continues running. There are too many different
interfaces to hardware RAID from what I've seen, such that you don't get
the same level of control and information reporting.