Re: LSI MegaRAID

[Tiziano Zito <opossumnano@gmail.com>]

Hi!

> Considering this seems to affect a very limited number of hardware I
> don't think it actually classifies as critical for kfreebsd after
> all.

I don't know how many SystemX servers IBM has sold in the last 6
months, but most of them mount this or other LSI cards based on the
same LSI MegaRAID SAS 2208 chip. So it may be a quite significant
amount of hardware...

> However, FreeBSD 9.0-stable ships a newer driver from LSI (maybe it's
> the same as the new mrsas driver mentioned in LSI's KB article?).
> 
> http://svnweb.freebsd.org/base/stable/9/sys/dev/mps/mps.c?view=log
> 
> I guess this driver is being used with FreeBSD at Netflix (they claim to
> use MPT2 controllers for their new CDN) and/or at Yahoo!;  note that
> scottl reviewed many of the fixes in the changelog:
> 
> http://lists.freebsd.org/pipermail/freebsd-stable/2012-June/068129.html
> 
> That suggests it would be technically possible to use the newer driver
> with kFreeBSD 9.0, but the diff would be large, and maybe not the sort
> of thing that could be introduced this late in the freeze for Wheezy?

I can not confirm that those are the same drivers. Comparing the
sources of the drivers shipped by LSI with that:

> http://svnweb.freebsd.org/base/releng/9.1/sys/dev/mps/mps.c?view=log

seems to indicate that they don't have anything to do with each
other. Maybe same chip but different card with different API? Or
maybe just a lot of refactoring... no idea.

Anyway, I managed to successfully install FreeBSD-9.0-RELEASE
following the instructions here (pages 26-35):
http://www.lsi.com/downloads/Public/MegaRAID%20Common%20Files/80-00163-01_RevG.pdf

The sources and the pre-compiled module can be found here:
http://www.lsi.com/downloads/Public/MegaRAID%20Common%20Files/MR_FreeBSD_DRIVER_2208-v05.504.05.00.tgz

As I was installing a stock kernel, for me it boiled down to just
copying the pre-compiled module mrsas.ko to /boot/kernel and add the following
two lines to /boot/loader.conf:
mfi_load="NO"
mrsas_load="YES"

So, all in all, for kfreebsd it would be a patch of 5524 lines, but
all concentrated in a single directory for a module that was not
present in kfreebsd before, so the probability of breaking something
else along the way seems pretty small. And, the module sources are
BSD licensed, so no problems with that either ;)

Ciao,
Tiziano