Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 5 Nov 2001 17:45:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 5 Nov 2001 17:45:02 -0500 Received: from vasquez.zip.com.au ([203.12.97.41]:48401 "EHLO vasquez.zip.com.au") by vger.kernel.org with ESMTP id ; Mon, 5 Nov 2001 17:44:49 -0500 Message-ID: <3BE71529.F781EF2A@zip.com.au> Date: Mon, 05 Nov 2001 14:39:37 -0800 From: Andrew Morton X-Mailer: Mozilla 4.77 [en] (X11; U; Linux 2.4.14-pre8 i686) X-Accept-Language: en MIME-Version: 1.0 To: Matthias Andree CC: lkml Subject: Re: disk throughput In-Reply-To: <3BE5F5BF.7A249BDF@zip.com.au>, <3BE5F5BF.7A249BDF@zip.com.au> <20011105132346.B5805@emma1.emma.line.org> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Matthias Andree wrote: > > On Sun, 04 Nov 2001, Andrew Morton wrote: > > > Numbers. The machine has 768 megs; the disk is IDE with a two meg cache. > > The workload consists of untarring, tarring, diffing and removing kernel > > trees. This filesystem is 21 gigs, and has 176 block groups. > > Does that IDE disk run with its write cache enabled or disabled? write-behind is enabled. I'm not religious about write-behind. Yes, there's a small chance that the disk will decide to write a commit block in front of the data (which is at lower LBAs). But a) It's improbable b) if it does happen, the time window where you need to crash is small. c) if your kernel crashes, the data will still be written. It has to be a power-down. But good point - I'll test without writebehind, and with SCSI. - - 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/