From: Nix <nix@esperi.org.uk>
To: linux-kernel@vger.kernel.org
Subject: sym53c8xx2: incredible sloth after parity error / SCSI bus reset
Date: Sun, 02 Dec 2007 00:14:21 +0000 [thread overview]
Message-ID: <878x4egdgi.fsf@hades.wkstn.nix> (raw)
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).
--
`Some people don't think performance issues are "real bugs", and I think
such people shouldn't be allowed to program.' --- Linus Torvalds
next reply other threads:[~2007-12-02 0:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-02 0:14 Nix [this message]
2007-12-06 22:31 ` sym53c8xx2: incredible sloth after parity error / SCSI bus reset Andrew Morton
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=878x4egdgi.fsf@hades.wkstn.nix \
--to=nix@esperi.org.uk \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).