Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 16 Jul 2002 13:24:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 16 Jul 2002 13:24:15 -0400 Received: from 216-42-72-142.ppp.netsville.net ([216.42.72.142]:6499 "EHLO roc-24-169-102-121.rochester.rr.com") by vger.kernel.org with ESMTP id ; Tue, 16 Jul 2002 13:24:15 -0400 Subject: Re: [Announce] device-mapper beta3 (fast snapshots) From: Chris Mason To: linux-lvm@sistina.com Cc: Andrew Theurer , Kevin Corry , linux-kernel@vger.kernel.org In-Reply-To: <20020716163157.GA11334@fib011235813.fsnet.co.uk> References: <3D2F6464.60908@us.ibm.com> <02071513565400.06209@boiler> <20020716084234.GA431@fib011235813.fsnet.co.uk> <200207161105.49328.habanero@us.ibm.com> <20020716163157.GA11334@fib011235813.fsnet.co.uk> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.8 Date: 16 Jul 2002 13:27:24 -0400 Message-Id: <1026840444.21656.544.camel@tiny> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 817 Lines: 22 On Tue, 2002-07-16 at 12:31, Joe Thornber wrote: > > Joe, are you absolutely sure these tests had the disk cache disabled? That's > > the only hardware thing I can think of that would make a difference. > > Absolutely sure. Those figures were for a pair of PVs that were > sharing an IDE cable so I can certainly get things moving faster. Some IDE drives ignore commands to turn off the write back cache, or turn it back on when load gets high. Try iozone -s 50M -i 0 -o with writeback on and off. If you get the same answer the benchmarks are suspect.... -chris - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/