From owner-freebsd-questions@FreeBSD.ORG Sat Aug 4 13:28:04 2012 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CDBE4106566B for ; Sat, 4 Aug 2012 13:28:04 +0000 (UTC) (envelope-from steve@sohara.org) Received: from uk1rly2283.eechost.net (relay01a.mail.uk1.eechost.net [217.69.40.75]) by mx1.freebsd.org (Postfix) with ESMTP id 8C2098FC14 for ; Sat, 4 Aug 2012 13:28:04 +0000 (UTC) Received: from [31.186.37.179] (helo=rpi-1.marelmo.com) by uk1rly2283.eechost.net with esmtpa (Exim 4.72) (envelope-from ) id 1SxeKO-0005ZW-Fk for freebsd-questions@freebsd.org; Sat, 04 Aug 2012 14:23:36 +0100 Received: from [192.168.63.1] (helo=steve.marelmo.com) by rpi-1.marelmo.com with smtp (Exim 4.72) (envelope-from ) id 1SxeOh-0001jp-Q9 for freebsd-questions@freebsd.org; Sat, 04 Aug 2012 14:28:03 +0100 Date: Sat, 4 Aug 2012 14:27:58 +0100 From: Steve O'Hara-Smith To: freebsd-questions@freebsd.org Message-Id: <20120804142758.0126fded.steve@sohara.org> X-Mailer: Sylpheed 3.1.3 (GTK+ 2.24.6; amd64-portbld-freebsd9.0) X-Face: %]+HVL}K`P8>+8ZcY-WGHP6j@&mxMo9JH6_WdgIgUGH)JX/usO0%jy7T~IVgqjumD^OBqX, Kv^-GM6mlw(fI^$"QRKyZ$?xx/ Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Auth-Info: 15567@permanet.ie (plain) Subject: ZFS bonnie puzzlement X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 04 Aug 2012 13:28:04 -0000 Hi, I've been looking at the performance of my new NAS box - built using a Jetway JNF99FL-525 with 4GB of 1066 DDR3 and a pair of 2TB Samsung F4 drives in a mirror. It all works but the performance reports are puzzling Running bonnie -s 8192 - reports character and block write times of around 66MB/s which is consistent with what zpool iostat -v and systat -v are showing me. Read performance OTOH is strange, zpool and systat both reporting consistently an aggregated read speed of around 120MB/s during the block read tests (which seems a bit slow for the drives - and indeed systat reports the drives at less than 50% utilisation) but bonnie is only reporting 35MB/s, I see similar discrepancies with simple dd block reads to /dev/null, in which case my stopwatch agrees with dd. I made some more bonnie tests on the boot SSD - there everything is as expected systat and bonnie agree and the disc gets pushed to 90-100% utilisation with write speeds over 100MB/s and read speeds over 250MB/s. Also a dd of the raw drive (read only of course) runs the drives up to around 130MB/s easily - dd and systat agree about the speed. First up can anyone explain the discrepancy between bonnie and zpool/systat for the XFS pool ? Secondly can anyone suggest a reason that I can't seem to get the drives above 50% reported utilisation on reads ? -- Steve O'Hara-Smith | Directable Mirror Arrays C:>WIN | A better way to focus the sun The computer obeys and wins. | licences available see You lose and Bill collects. | http://www.sohara.org/