Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263685AbTIHWYr (ORCPT ); Mon, 8 Sep 2003 18:24:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263688AbTIHWYr (ORCPT ); Mon, 8 Sep 2003 18:24:47 -0400 Received: from adsl-63-194-239-202.dsl.lsan03.pacbell.net ([63.194.239.202]:58130 "EHLO mmp-linux.matchmail.com") by vger.kernel.org with ESMTP id S263685AbTIHWYo (ORCPT ); Mon, 8 Sep 2003 18:24:44 -0400 Date: Mon, 8 Sep 2003 15:24:57 -0700 From: Mike Fedyk To: Oleg Drokin Cc: Rogier Wolff , Hans Reiser , linux-kernel@vger.kernel.org, Nikita Danilov Subject: Re: First impressions of reiserfs4 Message-ID: <20030908222457.GB17441@matchmail.com> Mail-Followup-To: Oleg Drokin , Rogier Wolff , Hans Reiser , linux-kernel@vger.kernel.org, Nikita Danilov References: <3F50D986.6080707@namesys.com> <20030831191419.A23940@bitwizard.nl> <20030908081206.GA17718@namesys.com> <20030908105639.B26722@bitwizard.nl> <20030908090826.GB10487@namesys.com> <20030908113304.A28123@bitwizard.nl> <20030908094825.GD10487@namesys.com> <20030908120531.A28937@bitwizard.nl> <20030908101704.GE10487@namesys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030908101704.GE10487@namesys.com> User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2584 Lines: 76 On Mon, Sep 08, 2003 at 02:17:04PM +0400, Oleg Drokin wrote: > You only can have as many inodes as number of blocks on the fs (at least that's the limit imposed on you > by mke2fs). True, but not exactly. Each file will need one block to store even one byte on ext2/3. But your inode tables have about 1/4-1/2 the number of inode entries to blocks. This can be changed at mkfs time though. # mke2fs -n -b 1024 -m0 /dev/md0 mke2fs 1.34-WIP (21-May-2003) Filesystem label= OS type: Linux Block size=1024 (log=0) Fragment size=1024 (log=0) 39923712 inodes, 319388032 blocks 0 blocks (0.00%) reserved for the super user First data block=1 38988 block groups 8192 blocks per group, 8192 fragments per group 1024 inodes per group 40M inodes and 319M blocks with a 1k block ext2/3 filesystem. # mke2fs -n -b 4096 -m0 /dev/md0 mke2fs 1.34-WIP (21-May-2003) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) 39927808 inodes, 79847008 blocks 0 blocks (0.00%) reserved for the super user First data block=0 2437 block groups 32768 blocks per group, 32768 fragments per group 16384 inodes per group 40M inodes and 80M blocks on a 4k block ext2/3 filesystem. So with the defaults, you'd have to have 40M files each between 4.1 - 7.9Kb to run out of inodes, and fill the filesystem. k# mke2fs -n -b 1024 -m0 -T news /dev/md0 mke2fs 1.34-WIP (21-May-2003) Filesystem label= OS type: Linux Block size=1024 (log=0) Fragment size=1024 (log=0) 79847424 inodes, 319388032 blocks 0 blocks (0.00%) reserved for the super user First data block=1 38988 block groups 8192 blocks per group, 8192 fragments per group 2048 inodes per group 80M inodes and 319M blocks on a 1k block ext2/3 filesystem. Now one question I have... Is that 32k blocks per group + 32k fragments per group = 64k blocks per group (since fragments aren't[1] implemented)? [1] For those interested, the space allocated for fragments was a perfect fit for tail merging support. There is a patch in alpha stages floating around for that... Hmm, take ext3 with htree, reiser3 & reiser4 (choose the block size 1k, 2k or 4k) with tail merging off, 1k files per directory and all files the same size as block size with 40M files. How would the table look as far as space effency look comparing them? For that matter, how do JFS & XFS compare? Mike - 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/