From owner-freebsd-fs@FreeBSD.ORG Sun Oct 11 18:18:44 2009 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D4A7E106566B for ; Sun, 11 Oct 2009 18:18:44 +0000 (UTC) (envelope-from josh@multipart-mixed.com) Received: from joshcarter.com (67-207-137-80.slicehost.net [67.207.137.80]) by mx1.freebsd.org (Postfix) with ESMTP id B65BF8FC1E for ; Sun, 11 Oct 2009 18:18:44 +0000 (UTC) Received: from [192.168.1.122] (dsl081-096-235.den1.dsl.speakeasy.net [64.81.96.235]) by joshcarter.com (Postfix) with ESMTPSA id 9D0511C003 for ; Sun, 11 Oct 2009 18:00:39 +0000 (UTC) Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes Mime-Version: 1.0 (Apple Message framework v1076) From: Josh Carter In-Reply-To: <4AD20B41.3070405@quip.cz> Date: Sun, 11 Oct 2009 12:00:36 -0600 Content-Transfer-Encoding: 7bit Message-Id: References: <4AD1616C.8060504@quip.cz> <4AD20B41.3070405@quip.cz> To: freebsd-fs@freebsd.org X-Mailer: Apple Mail (2.1076) Subject: Re: ZFS vs. df -h completely different size of filesystem [solved] X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 Oct 2009 18:18:44 -0000 Miroslav, > But space remains occupied by data of snapshots! Thats why df showed > just 24G size and not 360G. Df knows nothing about snapshots. Some additional factors to keep in mind when looking at ZFS and used/ available disk space: - Snapshots (as you discovered). - Compression: when compression is turned on (as you have), you can't know exactly how much more data will fit into the filesystem because it depends on how well the data compresses. - Sparse files: "ls -h" will show you how large a file says it is; "du -h" and "zfs list" should show how much space is actually used. These will disagree on sparse files. - Space reserved for copy-on-write: "zpool list" and "zfs list" will differ on available space because ZFS reserves some amount of slop space; truly running out of blocks is disastrous in a COW system. In general, learn to trust "zfs list" because the traditional tools don't know the full story. Best regards, Josh