Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161026AbXBOTib (ORCPT ); Thu, 15 Feb 2007 14:38:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161037AbXBOTib (ORCPT ); Thu, 15 Feb 2007 14:38:31 -0500 Received: from cantor2.suse.de ([195.135.220.15]:60438 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161026AbXBOTia (ORCPT ); Thu, 15 Feb 2007 14:38:30 -0500 To: Juan Piernas Canovas Cc: Jan Engelhardt , sfaibish , kernel list Subject: Re: [ANNOUNCE] DualFS: File System with Meta-data and Data Separation References: From: Andi Kleen Date: 15 Feb 2007 21:38:18 +0100 In-Reply-To: Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1297 Lines: 26 Juan Piernas Canovas writes: [playing devil's advocate here] > If the data and meta-data devices of DualFS can be on different disks, > DualFS is able to READ and WRITE data and meta-data blocks in > PARALLEL. XFS can do this too using its real time volumes (which don't contain any metadata). It can also have a separate log. Also many storage subsystems have some internal parallelism in writing (e.g. a RAID can write on different disks in parallel for a single partition) so i'm not sure your distinction is that useful. If you stripe two disks with a standard fs versus use one of them as metadata volume and the other as data volume with dualfs i would expect the striped variant usually be faster because it will give parallelism not only to data versus metadata, but also to all data versus other data. Also I would expect your design to be slow for metadata read intensive workloads. E.g. have you tried to boot a root partition with dual fs? That's a very important IO benchmark for desktop Linux systems. -Andi - 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/