I have basically the same system. BP6 (dual 400 SMP) + 2 UDMA66 Maxtor
Drives. Under
high I/O load, I get the lost disk contact messages. Sometimes I recover
from
the hang other times I have to hard reset the system.
Yes I know that maxtor is not the highest quality but at $120 for 13GB ;-)
Is there anything I can do to solve this problem besides buying new disks?
Dan
----- Original Message -----
From: "Hans Ottevanger" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Saturday, February 12, 2000 10:31 AM
Subject: ABIT BP6 + UDMA66: ad_timeout: lost disk contact
> Hi folks,
>
> I am currently having problems with my new Dual Celeron testsystem,
> when trying to use UDMA66.
>
> Hardware:
>
> ABIT BP6
> 2x Celeron 466 (NOT overclocked)
> 128 Mbyte RAM
> Matrox G400 16 MByte
> 3Com 905B
> 2x Maxtor 92041U4 20 GByte
> Aopen CDROM 48x
>
> One of the disks is master on the first "standard" disk channel, and
> uses
> UDMA33, the other is master on the first "fast" channel controlled by
> the
> on-board HPT-366, and is probed as UDMA66.
>
> When I use the UDMA33 disk, no problem occurs at all, I can even run
> "make buildworld" without any problems. When accessing the disk on the
> UDMA66 channel however, the system regularly hangs, followed by a
> message
> like:
>
> Feb 12 12:39:54 myhost /kernel: ad4: ad_timeout: lost disk contact -
> resetting
> Feb 12 12:39:54 myhost /kernel: ata2: resetting devices .. done
>
> After a few of these messages the system hangs completely, and needs to
> be
> rebooted.
>
> The problem already occurred during my first attempts to use UDMA66 last
> week, but now persists using today's 4.0-CURRENT.
> My kernel is derived from GENERIC, with SMP added, and devices removed
> that
> are not present. I do not yet use softupdates.
>
>
> The problem can easily be reproduced by creating a large file as
> follows:
>
> dd if=/dev/zero of=junk bs=1024k count=512
>
> This command runs without any problem. Reading this file with:
>
> dd if=junk of=/dev/null bs=1024k
>
> causes the problem to occur within a few seconds. Decreasing the
> blocksize
> makes the system survive somewhat longer, but the problem still occurs.
> Only with a blocksize lower than 4k the system does not hang.
>
> Very strange is the fact that reading the raw device file with:
>
> dd if=/dev/ad4s1c of=/dev/null bs=1024k
>
> completes without problems, even with two commands running concurrently.
>
> I already tried to swap the disks, but the problem still occurs on the
> one
> that is using UDMA66. Even when switching to PIO using 'sysctl', the
> system
> still hangs, it just takes somewhat longer before it happens.
>
> Does anybody have an idea what happens ?
>
>
> Kind regards,
>
> Hans
>
>
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