From owner-freebsd-hackers@FreeBSD.ORG Tue Jan 15 15:13:09 2013 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 0FADAE5E for ; Tue, 15 Jan 2013 15:13:09 +0000 (UTC) (envelope-from fullermd@over-yonder.net) Received: from thyme.infocus-llc.com (server.infocus-llc.com [206.156.254.44]) by mx1.freebsd.org (Postfix) with ESMTP id DF988EC0 for ; Tue, 15 Jan 2013 15:13:08 +0000 (UTC) Received: from draco.over-yonder.net (c-75-65-60-66.hsd1.ms.comcast.net [75.65.60.66]) (using TLSv1 with cipher ADH-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by thyme.infocus-llc.com (Postfix) with ESMTPSA id 70F5137B60E; Tue, 15 Jan 2013 09:06:53 -0600 (CST) Received: by draco.over-yonder.net (Postfix, from userid 100) id 3Ylvz00JqfzCq3; Tue, 15 Jan 2013 09:06:52 -0600 (CST) Date: Tue, 15 Jan 2013 09:06:52 -0600 From: "Matthew D. Fuller" To: Karim Fodil-Lemelin Subject: Re: IBM blade server abysmal disk write performances Message-ID: <20130115150651.GA3400@over-yonder.net> References: <50F563BE.7010609@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50F563BE.7010609@gmail.com> X-Editor: vi X-OS: FreeBSD User-Agent: Mutt/1.5.21-fullermd.4 (2010-09-15) X-Virus-Scanned: clamav-milter 0.97.6 at thyme.infocus-llc.com X-Virus-Status: Clean Cc: freebsd-hackers@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Jan 2013 15:13:09 -0000 On Tue, Jan 15, 2013 at 09:12:14AM -0500 I heard the voice of Karim Fodil-Lemelin, and lo! it spake thus: > > da0: Fixed Direct Access SCSI-6 device That's a 10k RPM drive. > FreeBSD 9.1: > > 10000+0 records in > 10000+0 records out > 5120000 bytes transferred in 60.024997 secs (85298 bytes/sec) 10000 ops in 60 seconds is practically the definition of a 10k drive. > CentOS: > > 100000+0 records in > 100000+0 records out > 51200000 bytes (51 MB) copied, 1.97883 s, 25.9 MB/s 10k ops in 2 seconds is 300k per second. You could make a flat-out *KILLING* if you could sell a platter drive that can pull that off. Presumably this is an instance of "Linux only has block devices for hard drives, not character devices", so you're getting your writes all buffered over there. Which is to say, nothing's wrong, you're just not measuring the same thing. -- Matthew Fuller (MF4839) | fullermd@over-yonder.net Systems/Network Administrator | http://www.over-yonder.net/~fullermd/ On the Internet, nobody can hear you scream.