Promise controller and 5.2

[Tom Glover]

On Fri, 16 Jan 2004, Doug White wrote:

> On Fri, 16 Jan 2004, Tom Glover wrote:
>
> >
> > I am running 5.2-RELEASE with a Promise S150 TX4 Serial ATA RAID
> > controller and a couple of WDC SATA drives at RAID 1. I am noticing some
> > behavior that does not seem right to me.
> >
> > Systems boots fine on the two mirrored drives. If I disconnect the drive
> > on channel 2 then the system continues to run. However if I disconnect the
> > drive on channel 1 it dies.
>
> Can you explain "dies"?

No response on console.

>
> > If I reboot after the drive on channel 1 fails I can recover and boot off
> > the drive on channel 2. However, the Promise S150 BIOS throws up an error
> > message about the drive failure that requires manual intervention before
> > boot can proceed.
>
> This is normal for Promise and most ATA RAID, since thats likely to be the
> only warning you'll get about a missing disk. Also, some operating systems
> are not good about bumping the generation numbers AT ALL, and you can end
> up with unsynchronized mirrors if you continue.  With the mirror, you
> won't lose your data, but its not designed to be fault-tolerant in a
> runtime sense.  I don't know why you get differing failure modes between
> disks, though -- perhaps you aren't using the right disk device?  You
> should be using ar0.
>
> > There does not appear to be any way around that. This, IMIHO, is brain
> > dead and makes the controller useless for any remote operation. If this
> > is SOP for Promise then can someone suggest a SATA RAID controller that
> > behaves in a more sane manner?
>
> You've discovered that ATA RAID is software RAID with hardware assist.
>
> If you want more transparent ATA RAID, you want 3ware.
>
> --
> Doug White                    |  FreeBSD: The Power to Serve
> dwhite at gumbysoft.com          |  www.FreeBSD.org
>

--
Tom Glover