Re: ICH5R SATA RAID?

[ resending from the address subscribed to the list... ]

On Tue, Apr 06, 2004 at 20:29:10 -0700, Doug Ambrisko wrote:
> Doug White writes:
> | On Thu, 1 Apr 2004, Mike Jakubik wrote:
> | 
> | > Hello,
> | >
> | > I recently purchased a Supermicro Intel P4 MB w/ 875P chipset (p4sce) with
> | > the assumption/hope that serial ata raid would function. However this does
> | > not seem so. After managing to install FreeBSD on a pata drive (the
> | > bootloader would crash if I used a cd to install when serial controller
> | > was enabled, had to use a floppy) and updating to latest ?current code,
> | > the raid controller is not recognized. This is what dmseg displays:
> | 
> | The Adaptec HostRAID mode of the ICH5 is not supported at this time.
> 
> Say what?  The ICH5 RAID is SW raid and it nothing more then the 
> SATA device with a different device ID when you flip a bit in the
> ICH.  It works just like a SATA device since it is.  Intel has a
> Promise like RAID bios extension to manage the SW RAID.
> 
> Now the Adaptec Chip which is not an ICH is a different beast.
> 
> The ICH5-R that the the p4sce is, is not the Adaptec thing.  Now
> there is an Adaptec SATA RAID card that I've played with that
> seems to work fine with the aac driver.  Don't know if this is
> the same that is on HostRAID motherboards.
> 
> I have support for this HW in -stable & -current.  I have not looked
> at decoding the Intel RAID configuration info.  However, if you are
> just doing mirroring you can safely ignore that for the most part.
> 
> At the minimum it is just a device ID change to the ICH5 SATA device.
> I do have some stability code to deal with SATA errors to prevent
> system hangs on media/device errors.
> 
> I have a SuperMicro system that does the Intel "ICH5-R" RAID.
> I should get inspired via the Linux code and see if I can add
> that.  So far I've haved setup the RAID but have turned on the ICH
> flag.

Adaptec HostRAID is software RAID.  By software RAID, I mean that you only
get BIOS support from the card for booting, and after that all of the RAID
functionality is handled via the host OS.

Some of their SCSI controllers include HostRAID support.  e.g.:

http://www.adaptec.com/worldwide/product/proddetail.html?sess=no&language=English+US&prodkey=ASC-39320A-R&cat=%2fTechnology%2fUltra320%2fNew+Ultra320+SCSI!

If the ICH5-R chip on the Supermicro motherboard in question has Adaptec
HostRAID BIOS, you would need support somewhere, either in the ATA code or
in Vinum or another RAID stack for reading the metadata and doing I/O to
the array.

There is Linux code to read the metadata here:

http://people.freebsd.org/~gibbs/linux/SRC/emd-0.8.0-tar.gz

And an older version here:

http://people.freebsd.org/~ken/linux/md.html

The metadata code in both drivers is dual licensed (BSD and GPL licenses),
so you could grab the metadata headers and use them to write support for it
for FreeBSD.

Ken
-- 
Kenneth Merry
ken_at_FreeBSD.org