From owner-freebsd-questions@FreeBSD.ORG Sun Nov 30 15:43:50 2008 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 98F9D106564A for ; Sun, 30 Nov 2008 15:43:50 +0000 (UTC) (envelope-from sahil@tandon.net) Received: from aegis.hamla.org (aegis.hamla.org [206.251.255.39]) by mx1.freebsd.org (Postfix) with ESMTP id 76B598FC14 for ; Sun, 30 Nov 2008 15:43:50 +0000 (UTC) (envelope-from sahil@tandon.net) Received: from localhost (localhost [127.0.0.1]) by aegis.hamla.org (Postfix) with ESMTP id 00C785C78 for ; Sun, 30 Nov 2008 10:45:16 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tandon.net; h= x-virus-scanned:in-reply-to:content-disposition:content-type :mime-version:references:reply-to:message-id:subject:from:date: received; s=aegis; t=1228059915; bh=ql/joAGqmhcXMOFxb+ZPZFIZXZDo HCKVfI0XgcoLoaQ=; b=qNaSAnpCP8zjrv80cJJ3gZzX3JFN433f9A5mHhPFH9Ws OHNf6YB3RbU0wZeGTeXkoZ5izzq2B+ZEg539li2GBnJ6Rbr+RsADjnF2a8phjL+X OAY3mkjmLJ+0ZdjDtEeADsBzPgA54Zh8v9MgAUozb461KY2J8oyt/pnhGRnA/JQ= Received: from aegis.hamla.org ([127.0.0.1]) by localhost (aegis.hamla.org [127.0.0.1]) (amavisd-new, port 10027) with LMTP id jsA0ZjTqdJLg for ; Sun, 30 Nov 2008 10:45:15 -0500 (EST) Date: Sun, 30 Nov 2008 10:43:49 -0500 From: Sahil Tandon To: freebsd-questions@freebsd.org Message-ID: <20081130154348.GB49413@shepherd> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Virus-Scanned: ClamAV version 0.94, clamav-milter version 0.94 on aegis.hamla.org X-Virus-Status: Clean Subject: Re: does not understand "df -H" X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: "freebsd-questions@freebsd.org" List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Nov 2008 15:43:50 -0000 Tsu-Fan Cheng wrote: > Hi, > I have a pretty basic question: when I "df -H" my disk, the numbers > cant add up, > > > Filesystem Size Used Avail Capacity Mounted on > /dev/ad0c 484G 429G 17G 96% /ad0c > > > there should be more disk space available based on what is shown. why > is this like that?? This is default behavior. From tunefs(8): -m minfree Specify the percentage of space held back from normal users; the minimum free space threshold. The default value used is 8%. Note that lowering the threshold can adversely affect perfor- mance: +o Settings of 5% and less force space optimization to always be used which will greatly increase the overhead for file writes. +o The file system's ability to avoid fragmentation will be reduced when the total free space, including the reserve, drops below 15%. As free space approaches zero, throughput can degrade by up to a factor of three over the performance obtained at a 10% threshold. Your df output suggests your minfree is set to the default 8%; to confirm this: % dumpfs /dev/ad0c | grep minfree | cut -f 1-2 -- Sahil Tandon