From owner-freebsd-fs@FreeBSD.ORG Wed Jan 4 01:34:10 2012 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 400111065780 for ; Wed, 4 Jan 2012 01:34:10 +0000 (UTC) (envelope-from bfriesen@simple.dallas.tx.us) Received: from blade.simplesystems.org (blade.simplesystems.org [65.66.246.74]) by mx1.freebsd.org (Postfix) with ESMTP id 001748FC0A for ; Wed, 4 Jan 2012 01:34:08 +0000 (UTC) Received: from freddy.simplesystems.org (freddy.simplesystems.org [65.66.246.65]) by blade.simplesystems.org (8.14.4+Sun/8.14.4) with ESMTP id q041Y7Vu015561; Tue, 3 Jan 2012 19:34:08 -0600 (CST) Date: Tue, 3 Jan 2012 19:34:07 -0600 (CST) From: Bob Friesenhahn X-X-Sender: bfriesen@freddy.simplesystems.org To: Jeremy Chadwick In-Reply-To: <20120103235108.GA25691@icarus.home.lan> Message-ID: References: <4F003EB8.6080006@dannysplace.net> <4F02FC42.1040103@dannysplace.net> <4F0311F2.7050209@brockmann-consult.de> <4F0312DF.8050004@brockmann-consult.de> <20120103162428.GA18661@icarus.home.lan> <20120103235108.GA25691@icarus.home.lan> User-Agent: Alpine 2.01 (GSO 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.2 (blade.simplesystems.org [65.66.246.90]); Tue, 03 Jan 2012 19:34:08 -0600 (CST) Cc: freebsd-fs@freebsd.org Subject: Re: ZFS With Gpart partitions 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: Wed, 04 Jan 2012 01:34:10 -0000 On Tue, 3 Jan 2012, Jeremy Chadwick wrote: >> >> There has been.quite a bit of discussion on this already and I think the >> safest way is to always 4k align as this works fine on.both drive types > > Agreed. The question is why FreeBSD isn't using those defaults in its > installer. As it happens, 4k alignment increases space consumption. A zfs metadata element which previously consumed just 512 bytes (really at least 1024 bytes due to redundancy) would then consume 4k bytes (or 8K bytes due to redundancy). Users with large numbers of small files have definitely noticed the loss of disk space. Users with 15K RPM SAS drives are likely to have different requirements than users with large SATA drives. The installer should obtain the requirements from the user and provide suitable warnings about the negative behavior which may occur from either option. Bob -- Bob Friesenhahn bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/