Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756674AbYCZIma (ORCPT ); Wed, 26 Mar 2008 04:42:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751578AbYCZImW (ORCPT ); Wed, 26 Mar 2008 04:42:22 -0400 Received: from fg-out-1718.google.com ([72.14.220.155]:25139 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751381AbYCZImV (ORCPT ); Wed, 26 Mar 2008 04:42:21 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=UyxjVm6UV6CJ6WwI0XAsjiOfWIFdJQzTbrjddPOQKxXaORiuO5FY5bJ2rS4dbXYEHjYNsVAfTFVg0pZu7hZjEfz/BeMXSZJ+/OEH6UYaLju17FhgEgCnJV5Qrt50iatzPwvhVb9iI41Yxyl1fYXSc7JB21yReGwpC2JiPOsqhp4= Message-ID: Date: Wed, 26 Mar 2008 09:42:19 +0100 From: "Bart Van Assche" To: "Emmanuel Florac" Subject: Re: RAID-1 performance under 2.4 and 2.6 Cc: linux-kernel@vger.kernel.org In-Reply-To: <20080325194306.4ac71ff2@galadriel.home> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080325194306.4ac71ff2@galadriel.home> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 781 Lines: 17 On Tue, Mar 25, 2008 at 7:43 PM, Emmanuel Florac wrote: > > dd if=/dev/zero of=/mountpoint/testfile bs=1M count=1024 Keep in mind that the above test tests two subsystems at the same time: RAID-1 + the filesystem on top of it. If you want to test RAID-1 performance you should specify a raw device to of=... instead of a file (and the direct I/O flags). There are considerable performance differences between filesystems for large files. E.g. XFS is a lot faster than ext3 for large files (gigabytes). Bart. -- 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/