From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267273AbUBMWtz (ORCPT ); Fri, 13 Feb 2004 17:49:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267271AbUBMWty (ORCPT ); Fri, 13 Feb 2004 17:49:54 -0500 Received: from willy.net1.nerim.net ([62.212.114.60]:2830 "EHLO willy.net1.nerim.net") by vger.kernel.org with ESMTP id S267304AbUBMWr6 (ORCPT ); Fri, 13 Feb 2004 17:47:58 -0500 Date: Fri, 13 Feb 2004 23:45:24 +0100 From: Willy Tarreau To: Linus Torvalds Cc: "Eric D. Mudama" , Timothy Miller , Linux Kernel Mailing List Subject: Re: File system performance, hardware performance, ext3, 3ware RAID1, etc. Message-ID: <20040213224524.GB13937@alpha.home.local> References: <402C0D0F.6090203@techsource.com> <20040213055350.GG29363@alpha.home.local> <20040213193046.GA17790@bounceswoosh.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 13, 2004 at 11:55:16AM -0800, Linus Torvalds wrote: > > the absolute worst-case write performance should be the same as read > > performance. > > That is only true if the disk block-size is smaller than the IO blocksize. > Can somebody fill me in on what modern disks do, especially the > high-density ones? This is purely hypothetical, but perhaps write-precompensation or the signal intensity or shape in the head implies to write at "safer" frequencies ? we're speaking about hundreds of megahertz, and I've always wondered what the signal looks like when it reaches the head. Cheers, Willy