Problems installing onto DAC960 (Mylex Acceleraid250)

Scott Long scottl at
Mon Dec 29 09:14:30 PST 2003

Michael Alexander wrote:
> Hello,
> (Please excuse the cross post, I'm not sure if this is more a scsi or
> general hardware question, it can go eitherway)
>   I had asked this question in freebsd-questions, but haven't been able to
> receive a decent answer.  A couple times I've gotten the answer that FreeBSD
> may not install onto RAID at all, I can't believe that is correct.  And that
> RAID is just for user data, not the OS.  Also working in the Netware world,
> I know that RAID is important for the entire server, especially the OS.

You are correct, it is certainly possible to install the OS onto any
RAID storage device that FreeBSD recognises.  There is an issue with
some low-end software raid controllers, but that does not apply here.

>   I am trying to install FreeBSD4.9 (or 5.1 even) on a system that uses a
> Mylex Acceleraid250 (DAC960 driver) without success.  The install CD hangs
> when it attempts to spin up the drives on the raid, waiting 15 seconds for
> scsi devices to settle is the last message on the screen.  I found that
> there is a similar problem with RH9, but that they have a work around, which
> involves recompiling the kernel and remaking the installation CDs.  I have
> the instructions for RH9, but I was hoping to be able to use FreeBSD.  If I
> can't get it installed though, I will have to go to RedHat instead.
> is the instructions, it is
> just a simple changing of two kernel options.  Is this possibly the same
> reason that I cannot install FreeBSD?  The two kernel options to be changed
> are the following:
>     # CONFIG_X86_UP_APIC is not set
>     # CONFIG_X86_UP_IOAPIC is not set
> Change them to:
>     CONFIG_X86_UP_APIC=y

The hang at the 'Waiting 15 seconds...' is likely not related to SCSI.
While the DAC960 card uses SCSI, it's FreeBSD driver does not attach
through the SCSI subsystem at all.  99% os hangs that happen at this
point are due to incorrect interrupt routing.  The RedHat work-around
appears to confirm this.  There really is no fix for 5.1 and 4.9 unless
you can experiment with moving the DAC960 to a different PCI slot.
FreeBSD 5.2 has a much more comprehesive interrupt routing algorithm and
will likely address your problem.  If the 5.2 CD doesn't work, try
booting it with ACPI disabled (either via the BIOS or the boot menu).

> If so, are there instructions like the RH ones?  I have never used FreeBSD
> before, I have used RH7 and 8.  Since RH is not really offering itself free
> anymore, I thought I would give FreeBSD a try, and it also appears that
> FreeBSD is abit more current in its packages than RH has been.  I do have
> another machine I can install onto to make the changes.  Since this system
> is going to be a mail server for the company, we want to be able use RAID
> for the entire system including boot.  The system is fully up to date on
> bios and firmware for both MB and raid card.


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