[K12OSN] Woe is me: Onboard SCSI/RAID Controller

Debbie Schiel debbie at redeemer.qld.edu.au
Sun Oct 17 03:13:52 UTC 2004

Hi Robert, That was very good news, very encouraging, and yes it did 
help enormously.

I tried installing K12ltsp 4.1.0 with no luck.
Then I tried 4.1.1 as suggested but same result.
I tried a 'linux dd' with the aic79xx driver from the Gibbs website - 
nope. Then I tried 3.1.2 which you said you have no problems with and... 
SUCCESS, it installed! I must admit I also had a lot of over-the-phone 
help from a contact down in ACT.

However, now I have a version of K12 that I am unfamiliar with and I 
can't connect it to the net, or to my demo clients, plus my fix for 
adding a usb key (which worked on 4.1.0) doesn't work... *sigh*

So on one hand I have a sooper dopper G700 with 3.1.2 and I'm not 
getting anywhere with it (yet!); and on the other hand I have my demo 
PIII with 4.1.0 that can support a couple clients but is as slow as...

All part of the fun of FOSS I suppose!

Best regards,


Robert Arkiletian wrote:
> Hi Debbie,
> I have good news. I am using this SCSI controller chip AIC7902W with super
> stability/performance in my school. I researched the chip before I bought it. It
> has very affordable scsi performance.
> I got an intel server board with the chip. The docs say it supports HOST raid.
> However, Linux does NOT support Host Raid. Host raid is actually software raid
> for Windows (ITS NOT HARDWARE RAID). There are drivers for Windows to make it
> work but not for Linux. However, the linux kernel will support software raid
> using LVM, which is just as fast as some hardware raid setups. (Although I have
> not tried it, I know it's done when you setup your partitions) The beautiful
> aspect of the AIC7902W is that is has TWO scsi channels. So you can have the
> full throughput of each channel and raid them through the kernel. All I did was
> use one scsi drive for / and another for /home. I have not tried raid. I'm using
> k12ltsp 3.1.2 (redhat 9) and not 4.1.1 (FC2). 32 clients == no problem.
> A couple of notes. You MUST disable HostRaid in the bios for the controller to
> work with Linux. Also, I down graded each scsi channel to 160 mb/s instead of
> the 320 mb/s (default). The system was not fully stable at 320mb/s because of
> scsi driver issues. Don't worry though a new 10k rpm scsi drive only needs
> around 60 mb/s bandwidth. So you should be okay for about 3 drives/channel at
> full throttle for all of them (highly unlikely). I don't think you will ever
> need more than 6 scsi drives for k12ltsp. The driver for the kernel is written
> by Justin Gibbs. He had some issues/disagreements with James Bottomley (kernel
> maintainer) and Linus Torvalds. So he pulled the drivers before version 2.0.x
> from his site. The 2.6 series kernel has stable adaptec scsi aic79xx driver
> 1.3.x in it. But if you go with k12ltsp 4.0.1 (FC1 & kernel 2.4.22) or earlier
> you will have to use a driver update disk (DUD) from here (versin > 2.0)
> http://people.freebsd.org/~gibbs/linux/
> these are stable too but the kernel maintainers are wary of them for technical
> reasons beyond my comprehension.
> This DUD disk has to be made with "dd" and must be used during installation of
> the OS in Expert mode.
> If you go with k12ltsp 4.1.1 (FC2) , no worries, it has stable scsi adaptec
> aic79xx driver 1.3.x built in since it comes with kernel 2.6.5
> If I was you, I would go with k12ltsp 4.1.1 (FC2) from the beginning. It will be
> the easiest for you. I did not have this option when I started. Just don't
> forget to disable HostRaid in the SCSI bios and lower the throughput to 160mb/s
> for each channel and you should be good to go. Also make sure your scsi cables
> are high quality and terminated properly.
> Hope that helps
> Good luck
> BTW the drivers on adaptec/intel sites are very old (don't use them)
> Robert Arkiletian


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