Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 7 Oct 2002 22:31:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 7 Oct 2002 22:31:41 -0400 Received: from h24-87-160-169.vn.shawcable.net ([24.87.160.169]:53890 "EHLO oof.localnet") by vger.kernel.org with ESMTP id ; Mon, 7 Oct 2002 22:31:40 -0400 Date: Mon, 7 Oct 2002 19:36:54 -0700 From: Simon Kirby To: Andrew Morton Cc: Chris Friesen , Daniel Phillips , "Martin J. Bligh" , Oliver Neukum , Rob Landley , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: The reason to call it 3.0 is the desktop (was Re: [OT] 2.6 not 3.0 - (NUMA)) Message-ID: <20021008023654.GA29076@netnation.com> References: <1281002684.1033892373@[10.10.2.3]> <3DA1D30E.B3255E7D@digeo.com> <3DA1D969.8050005@nortelnetworks.com> <3DA1E250.1C5F7220@digeo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3DA1E250.1C5F7220@digeo.com> User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1775 Lines: 38 On Mon, Oct 07, 2002 at 12:36:48PM -0700, Andrew Morton wrote: > Block allocators are fertile grounds for academic papers. It's > complex. There is a risk that you can do something which is > cool in testing, but ends up exploding horridly after a year's > use. By which time we have ten million deployed systems running like > dogs, damn all we can do about it. > > The best solution is to use first-fit and online defrag to fix the > long-term fragmentation. It really is. There has been no appreciable > progress on this. > > A *practical* solution is to keep a spare partition empty and do > a `cp -a' from one partition onto another once per week and > swizzle the mountpoints. Because the big copy will unfragment > everything. Having seen fragmentation issues build up on (mbox) mail spools over several years first hand, I can say that mail spools definitely show the need for a defragmentation tool. I remember actually doing the "cp -a" trick just to restore the mail server to decent performance (which worked amazingly well, for another few months). (This was before we switched to hashed directories and a POP3 server which caches mbox messages offsets/UIDLs/states.) Being able to defragment online would be very useful. I've seen some people talk about this every so often. How far away is it? Simon- [ Simon Kirby ][ Network Operations ] [ sim@netnation.com ][ NetNation Communications ] [ Opinions expressed are not necessarily those of my employer. ] - 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/