Working ZFS RAID/SAS controller support/mpii

[Peter Kay <syllopsium%syllopsium.co.uk@localhost>]

Configuration : Boot drive on SATA, other drives on LSI 3008 8i SAS in
JBOD, boot ROM disabled. The mpii driver gets very upset (causes a
kernel panic on boot, even though the boot drive is on SATA [1]) if
some of the drive bays aren't occupied, throws unhappy messages about
drives disappearing from bays, and generally doesn't provide any
confidence that I could ever remove a drive from a running system and
have it work.

I have an end goal of setting up a mirrored NetBSD root partition
(Raidframe as there is no other option), and then fault tolerant ZFS
for other storage. Is there a viable configuration with an external
SAS controller?

I do note that mpii(4) says

'The chips supported by mpii do not use a SCSI-like identifier.
Instead they use an opaque ID and leave discovery order up to the
operating system.  The code to handle this is currently not
implemented and therefore it is not a good idea to run this driver on
a multi-boot machine'

I take it from this that things like disk swapping and re-ordering are
just likely to result in extreme pain for mpii. Is there an SAS
controller (preferably 12Gb/s) that supports the disks in JBOD, and
will work if disks are removed?

My fallback position is to use SATA for everything for now, but I'd rather not.

[1] Yes, I did try with the SAS ROM set to Boot support, and the boot
drive on the SAS controller. This generally leads to more pain, and
again if disks are removed/moved (not the boot disk), can lead to
kernel panics even though the boot disk has not physically moved. Yes,
the SATA controller was still enabled, it needs to be as I'm using
more than 8 disks.

Cheers!