From owner-freebsd-stable@FreeBSD.ORG Sat Aug 14 03:29:30 2010 Return-Path: Delivered-To: stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D8481106566C for ; Sat, 14 Aug 2010 03:29:30 +0000 (UTC) (envelope-from tj@tjvarghese.com) Received: from mail-bw0-f54.google.com (mail-bw0-f54.google.com [209.85.214.54]) by mx1.freebsd.org (Postfix) with ESMTP id 712D48FC08 for ; Sat, 14 Aug 2010 03:29:30 +0000 (UTC) Received: by bwz20 with SMTP id 20so352552bwz.13 for ; Fri, 13 Aug 2010 20:29:29 -0700 (PDT) MIME-Version: 1.0 Received: by 10.204.56.14 with SMTP id w14mr1274719bkg.187.1281755218883; Fri, 13 Aug 2010 20:06:58 -0700 (PDT) Received: by 10.204.62.133 with HTTP; Fri, 13 Aug 2010 20:06:58 -0700 (PDT) In-Reply-To: <20100814021235.A12771CC3A@ptavv.es.net> References: <20100813213205.GB29150@slackbox.erewhon.net> <20100814021235.A12771CC3A@ptavv.es.net> Date: Sat, 14 Aug 2010 11:06:58 +0800 Message-ID: From: TJ Varghese To: Kevin Oberman Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: Roland Smith , stable@freebsd.org Subject: Re: Inconsistent IO performance X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 14 Aug 2010 03:29:30 -0000 > > > Maybe there is a hardware component here? Are both disks on the same > > controller? Or if not are both controllers using the same interrupt line? > > No. Each is on its one controller and is the only disk on that > controller. > > > You should have a look at 'systat -vmstat' with dd running in the > > background. That might give a clue as to where the bottleneck is. > > > You're using a laptop with 2 HDDs, so does that mean you're using the Ultrabay for the 2nd HDD? Perhaps anything connected to that drops down to ATA33 (pure speculation on my part) since it was designed for optical drives ...dmesg/atacontrol logs would be useful here. You may want to try dd with the of=/dev/null instead to remove the 2nd variable and benchmark solely the read speed of the 1st hdd. regards, TJ