From: Andrew Morton <akpm@linux-foundation.org>
To: Nix <nix@esperi.org.uk>
Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: Re: sym53c8xx2: incredible sloth after parity error / SCSI bus reset
Date: Thu, 6 Dec 2007 14:31:30 -0800 [thread overview]
Message-ID: <20071206143130.08ad8915.akpm@linux-foundation.org> (raw)
In-Reply-To: <878x4egdgi.fsf@hades.wkstn.nix>
On Sun, 02 Dec 2007 00:14:21 +0000
Nix <nix@esperi.org.uk> wrote:
> About once a year I get a SCSI parity error on one of my systems (the
> only one with SCSI). I presume the cabling is substandard, but given my
> coordination deficits and the rarity of the errors I'd do far more
> damage replacing it than leaving it be.
>
> I had one of these today.
>
> The system (2.6.23.9) spotted the error, and seemingly recovered:
>
> Dec 1 12:53:40 loki warning: kernel: sym0: SCSI parity error detected: SCR1=132 DBC=50000000 SBCL=0
> Dec 1 12:53:40 loki warning: kernel: sym0:0: ERROR (81:0) (8-0-0) (10/9d/0) @ (mem c2800048:ffffffff).
> Dec 1 12:53:40 loki warning: kernel: sym0: regdump: da 00 00 9d 47 10 00 0e 00 08 80 00 80 00 0f 0a d0 58 3c 01 02 ff ff ff.
> Dec 1 12:53:40 loki warning: kernel: sym0: SCSI BUS reset detected.
> Dec 1 12:53:40 loki notice: kernel: sym0: SCSI BUS has been reset.
>
> However, after that reset I/O to any device on that controller is
> *incredibly* slow.
>
> A monthly RAID check kicked off shortly afterwards and provided my first
> clue. Load average >15, and:
>
> md1 : active raid5 sda6[0] hdc5[3] sdb6[1]
> 76807296 blocks super 1.2 level 5, 64k chunk, algorithm 2 [3/3] [UUU]
> [========>............] check = 42.8% (16450780/38403648) finish=253.3min speed=1442K/sec
>
> 1442Kb/s is a bit less than I'd expect from a three-drive array with
> disks capable of 40Mb/s easily.
>
> /dev/sda:
> Timing buffered disk reads: 8 MB in 3.50 seconds = 2.29 MB/sec
>
> A somewhat slower ATAPI disk on the same machine:
>
> /dev/hdc:
> Timing buffered disk reads: 110 MB in 3.05 seconds = 36.08 MB/sec
>
> So, um, what could cause this? Can I speed it up again other than by
> rebooting (which I'm just about to do, but it is annoying).
>
cc linux-scsi.
Nothing is likely to happen. Please raise a report at bugzilla.kernel.org.
prev parent reply other threads:[~2007-12-06 22:31 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-02 0:14 sym53c8xx2: incredible sloth after parity error / SCSI bus reset Nix
2007-12-06 22:31 ` Andrew Morton [this message]
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