From owner-freebsd-fs@FreeBSD.ORG Thu Jan 11 20:23:58 2007 Return-Path: X-Original-To: freebsd-fs@freebsd.org Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 8C49516A415 for ; Thu, 11 Jan 2007 20:23:58 +0000 (UTC) (envelope-from ahnjoan@gmail.com) Received: from ug-out-1314.google.com (ug-out-1314.google.com [66.249.92.174]) by mx1.freebsd.org (Postfix) with ESMTP id ECAED13C457 for ; Thu, 11 Jan 2007 20:23:57 +0000 (UTC) (envelope-from ahnjoan@gmail.com) Received: by ug-out-1314.google.com with SMTP id o2so532174uge for ; Thu, 11 Jan 2007 12:23:53 -0800 (PST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=ojJPhEUGjlprU2PXl3dxtIGwwHGVZyFEkDSlmbhU5L2j7obJXPHTGM7cBhvZb7UJCdHgU4AMq9zmxDEntxVCcKlUE/ZEXyLmctsxK+OCmlzQhdK/lRZHS7bNgeNn4yLG7zQitcp4ZOxwBebRSHf+0FCr6BrGdqtJDr7Wacs1sGU= Received: by 10.78.149.15 with SMTP id w15mr669425hud.1168545347221; Thu, 11 Jan 2007 11:55:47 -0800 (PST) Received: by 10.78.11.6 with HTTP; Thu, 11 Jan 2007 11:55:47 -0800 (PST) Message-ID: <5e575c8a0701111155l859d0ecif617dbda43cef842@mail.gmail.com> Date: Thu, 11 Jan 2007 14:55:47 -0500 From: "Ahnjoan Amous" To: freebsd-fs@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Subject: aac scsi raid driver performance X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Jan 2007 20:23:58 -0000 I'm trying to find possible explanations for slow concurrent writes through the aac driver. This machine runs under 1% load and has less than 4 transfers per second to the drives in question when not being used for testing. When I attempt sequential "dd"s as follow, the results are better then 70MB/sec. dd if=/dev/zero of=/data02/helloworld bs=1m count=1000 1048576000 bytes transferred in 13.886718 secs (75509274 bytes/sec) dd if=/dev/zero of=/data03/helloworld bs=1m count=1000 1048576000 bytes transferred in 14.011323 secs (74837758 bytes/sec) When I attempt concurrent "dd"s as follow, with a 1 second sleep interval between starts, the results are better than 40MB/sec dd if=/dev/zero of=/data02/helloworld bs=1m count=1000 & sleep 1 dd if=/dev/zero of=/data03/helloworld bs=1m count=1000 & 1048576000 bytes transferred in 25.269555 secs (41495626 bytes/sec) 1048576000 bytes transferred in 24.935765 secs (42051086 bytes/sec) When I attempt concurrent "dd"s as follow, the results are little better than 20MB/sec dd if=/dev/zero of=/data02/helloworld bs=1m count=1000 & dd if=/dev/zero of=/data03/helloworld bs=1m count=1000 & 1048576000 bytes transferred in 44.963408 secs (23320652 bytes/sec) 1048576000 bytes transferred in 45.010065 secs (23296478 bytes/sec) I can't account for what causes the huge difference however the results are reproducible. I've run the tests dozens and dozens of times now, first blaming the em driver for my slow ggatec/ggated results, then GEOM for my slow local mirroring after eliminating the network, and finally blaming the aac driver after removing GEOM from the equation. If anyone has ideas on what I might look at or change or test I would love to hear. ****** Misc. Information ****** root:somehost:~ > df -k Filesystem 1K-blocks Used Avail Capacity Mounted on /dev/aacd2s1e 2026030 1024532 839416 55% /data02 /dev/aacd3s1e 2026030 1024532 839416 55% /data03 Hardware - aac - Dell PERC3/Di U160 aacd2 - hardware RAID 0, w/1 U320 300G drive aacd3 - hardware RAID 0, w/1 U320 300G drive