From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262433AbTJGOpJ (ORCPT ); Tue, 7 Oct 2003 10:45:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262434AbTJGOpJ (ORCPT ); Tue, 7 Oct 2003 10:45:09 -0400 Received: from thebsh.namesys.com ([212.16.7.65]:63717 "HELO thebsh.namesys.com") by vger.kernel.org with SMTP id S262433AbTJGOpE (ORCPT ); Tue, 7 Oct 2003 10:45:04 -0400 From: Nikita Danilov MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16258.53615.17755.970961@laputa.namesys.com> Date: Tue, 7 Oct 2003 18:45:03 +0400 To: Andreas Dilger Cc: "E. Gryaznova" , linux-kernel@vger.kernel.org Subject: Re: Can dbench be used for benchmarking fs? In-Reply-To: <20031007082944.D1564@schatzie.adilger.int> References: <3F82B4C6.707221A@namesys.com> <20031007082944.D1564@schatzie.adilger.int> X-Mailer: ed | telnet under Fuzzball OS, emulated on Emacs 21.5 (beta14) "cassava" XEmacs Lucid Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andreas Dilger writes: > On Oct 07, 2003 16:42 +0400, E. Gryaznova wrote: > > I use dbench for benchmarking the file systems and some results are > > suspicious for me. > > : > > : > > : > > As the result: the measuring deviation is equal = 23.4062 - 15.7005 = > > 7.7057 or about ~38% from average value. > > > > So, I have 2 questions : > > 1. Is there a way to avoid such big deviations on measuring a file > > systems throughput and to get more stable results? > > 2. Can dbench be used for benchmarking the file systems and if it is so > > -- what is the predictable error on the measuring? > > Dbench is not a good filesystem benchmark, because it deletes all of the > files at the end. Use something else for the filesystem benchmark - there Err... What is wrong with deleting all files at the end? Or do you mean it should mix file operations during run? > are lots of them (bonnie, iozone, mongo, etc). But why variance is so large? Another probably interesting observation is that dbench works faster on ext2 if it is run directly after mkfs.ext2, that is, without reboot between mkfs and mount. > > Cheers, Andreas Nikita.