From owner-freebsd-questions@FreeBSD.ORG Wed Sep 29 09:15:14 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0FC99106566C for ; Wed, 29 Sep 2010 09:15:14 +0000 (UTC) (envelope-from cyberleo@cyberleo.net) Received: from paka.cyberleo.net (paka.cyberleo.net [66.219.31.21]) by mx1.freebsd.org (Postfix) with ESMTP id D7C0A8FC22 for ; Wed, 29 Sep 2010 09:15:13 +0000 (UTC) Received: from [172.16.44.4] (dsl253-036-039.chi1.dsl.speakeasy.net [66.253.36.39]) by paka.cyberleo.net (Postfix) with ESMTPSA id ADE0228405; Wed, 29 Sep 2010 05:15:12 -0400 (EDT) Message-ID: <4CA303A0.10102@cyberleo.net> Date: Wed, 29 Sep 2010 04:15:12 -0500 From: CyberLeo Kitsana User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.9) Gecko/20100911 Lightning/1.0b3pre Thunderbird/3.1.3 MIME-Version: 1.0 To: Aaron References: In-Reply-To: X-Enigmail-Version: 1.1.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-questions@freebsd.org Subject: Re: Disappearing available space with ZFS...what am I missing? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 29 Sep 2010 09:15:14 -0000 On 09/29/2010 12:56 AM, Aaron wrote: > I've created a ZFS pool with zpool create tank raidz ada0 ada1 ada2 > ada3, and then I add some additional mountpoints (I think they're > called) using zfs create tank/storage, etc. In zpool list, I see the > pool with 3.62T available. With df -h, I see 2.4T available for tank, > and tank/storage. When I first created tank, it had the 3.62T > available as I expected. What am I missing? I do have compression set > to gzip-9 on tank which gets inherited like I want, don't know if that > would affect anything. zpool list shows raw space, and zfs list (and, to a certain extent, df) shows effective capacity. You've configured a raidz, which chews up extra space to store the redundant parity information; thus, for a 4-disk raidz, 1GB of stored data will use up about 1.33GB of raw space. Since effective capacity in ZFS is so variable, due to things like ditto blocks, raidz, compression, and (soon to be added) dedup, the numbers provided by df no longer make much sense. This blog posting can provide further elaboration as to why df doesn't work for advanced file storage: http://www.c0t0d0s0.org/archives/6168-df-considered-problematic.html -- Fuzzy love, -CyberLeo Technical Administrator CyberLeo.Net Webhosting http://www.CyberLeo.Net Furry Peace! - http://wwww.fur.com/peace/