From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:33020 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932361AbbDJKka (ORCPT ); Fri, 10 Apr 2015 06:40:30 -0400 Date: Fri, 10 Apr 2015 18:40:15 +0800 From: Liu Bo To: Russell Coker Cc: linux-btrfs@vger.kernel.org Subject: Re: du accuracy Message-ID: <20150410104015.GB10185@localhost.localdomain> Reply-To: bo.li.liu@oracle.com References: <201504101125.58088.russell@coker.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <201504101125.58088.russell@coker.com.au> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Fri, Apr 10, 2015 at 11:25:57AM +1000, Russell Coker wrote: > I'm copying an image of a 2G microSD card to a BTRFS filesystem. The SD card > is from an Android phone and is almost full of Android packages and photos, > there's very little space on the filesystem and what space there is probably > isn't filled with zeros. > > # ls -l > total 888000 > -rw-r--r--. 1 root root 1043529728 Apr 10 11:20 2gsd > > While doing it I run ls commands to see the progress and get output like the > above. Why is the file size according to ls not matching the total used? > > # du -h > 886M . > > When I ran du immediately afterwards it also reported that there was less than > 1G used. > > # du -h > 1.2G . > # du -h > 1.2G . > # du -h > 1.1G . > # du -h > 1.1G . > # du -h > 1.1G . > # du -h > 1.2G . > # du -h > 1.2G . > > Above are some consecutive du runs. Why does the space used go from 1.2G to > 1.1G before going up again? The file was created by "cat /dev/sde > 2gsd" so > it definitely wasn't getting smaller. > > What's going on here? What's your mount options? with autodefrag or compression? Thanks, -liubo > > -- > My Main Blog http://etbe.coker.com.au/ > My Documents Blog http://doc.coker.com.au/ > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html