From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Sandeen Subject: Re: 5% diskspace used for ext4? Date: Sun, 13 Jul 2008 18:41:12 -0500 Message-ID: <487A9298.8040707@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: Christian Kujau Return-path: Received: from mx1.redhat.com ([66.187.233.31]:49270 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754274AbYGMXlX (ORCPT ); Sun, 13 Jul 2008 19:41:23 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: Christian Kujau wrote: > Hi, > > I suspect this being a FAQ already, but I could not find[0] it: > does ext4 really use 5% of available space for internal housekeeping? > After formatting and mounting a ~917GB partition I see: > > # df -h /mnt/bench/ > Filesystem Size Used Avail Use% Mounted on > /dev/sdb1 917G 200M 871G 1% /mnt/bench > > The "200 MB used" would seem more sensible, but the difference between > "available" and "size" is really 46 GB. How comes? > > Thanks, > Christian. > > [0] http://ext4.wiki.kernel.org/index.php/Frequently_Asked_Questions > > PS, a few more details how the filesystem got created and mounted: > > # /opt/e2fsprogs/sbin/mkfs.ext4 -V > mke2fs 1.41.0 (10-Jul-2008) > Using EXT2FS Library version 1.41.0 > > # /opt/e2fsprogs/sbin/mkfs.ext4 /dev/sdb1 > [...] Somewhere in [...] was: XXX blocks (5.00%) reserved for the super user this can be tuned and maybe should actually be on a sliding scale for larger filesystems. -Eric