From owner-freebsd-questions@FreeBSD.ORG Mon Feb 8 14:30:29 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 C304B106566B for ; Mon, 8 Feb 2010 14:30:29 +0000 (UTC) (envelope-from m.seaman@black-earth.co.uk) Received: from smtp.infracaninophile.co.uk (gate6.infracaninophile.co.uk [IPv6:2001:8b0:151:1::1]) by mx1.freebsd.org (Postfix) with ESMTP id E3AC28FC14 for ; Mon, 8 Feb 2010 14:30:28 +0000 (UTC) Received: from seedling.black-earth.co.uk (seedling.black-earth.co.uk [81.187.76.163]) (authenticated bits=0) by smtp.infracaninophile.co.uk (8.14.4/8.14.4) with ESMTP id o18EUNMW024958 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Mon, 8 Feb 2010 14:30:24 GMT (envelope-from m.seaman@black-earth.co.uk) X-DKIM: Sendmail DKIM Filter v2.8.3 smtp.infracaninophile.co.uk o18EUNMW024958 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=black-earth.co.uk; s=201001-black-earth; t=1265639424; bh=W4E5Z9H/f//rQYsOHZ8oiDVqwWUMCbzIqYjBMrAZjKk=; h=Message-ID:Date:From:MIME-Version:To:CC:Subject:References: In-Reply-To:Content-Type:Cc:Content-Type:Date:From:In-Reply-To: Message-ID:Mime-Version:References:To; z=Message-ID:=20<4B701FF8.20203@black-earth.co.uk>|Date:=20Mon,=200 8=20Feb=202010=2014:30:16=20+0000|From:=20Matthew=20Seaman=20|User-Agent:=20Mozilla/5.0=20(Macintosh=3B= 20U=3B=20Intel=20Mac=20OS=20X=2010.6=3B=20en-GB=3B=20rv:1.9.1.7)=2 0Gecko/20100111=20Thunderbird/3.0.1|MIME-Version:=201.0|To:=20Pete r=20Steele=20|CC:=20"freebsd-questions@free bsd.org"=20|Subject:=20Re:=20Should =20root=20partition=20be=20first=20partition?|References:=20<7B939 7B189EB6E46A5EE7B4C8A4BB7CB383B25CD@MBX03.exg5.exghost.com>|In-Rep ly-To:=20<7B9397B189EB6E46A5EE7B4C8A4BB7CB383B25CD@MBX03.exg5.exgh ost.com>|X-Enigmail-Version:=201.0|Content-Type:=20multipart/signe d=3B=20micalg=3Dpgp-sha1=3B=0D=0A=20protocol=3D"application/pgp-si gnature"=3B=0D=0A=20boundary=3D"------------enig427078F4DDD28AD6C2 FF4AEA"; b=ID7Yls7Id2DUe68U0vOpN8PMoBFSidqwVvunklXU6ZReDE1FoWTZ0oOzPmn98m9ja 0FGtv8T7cCmvZAApZIAu7w1G0v0w5xHBGDNquMfrEMYXPJqaOX5fCXYrdEKZDU9Pb/ CDKyGmOlWqDkiGtze7FMhHcJsnjEjys5RVhRNDmU= Message-ID: <4B701FF8.20203@black-earth.co.uk> Date: Mon, 08 Feb 2010 14:30:16 +0000 From: Matthew Seaman User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-GB; rv:1.9.1.7) Gecko/20100111 Thunderbird/3.0.1 MIME-Version: 1.0 To: Peter Steele References: <7B9397B189EB6E46A5EE7B4C8A4BB7CB383B25CD@MBX03.exg5.exghost.com> In-Reply-To: <7B9397B189EB6E46A5EE7B4C8A4BB7CB383B25CD@MBX03.exg5.exghost.com> X-Enigmail-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig427078F4DDD28AD6C2FF4AEA" X-Virus-Scanned: clamav-milter 0.95.3 at happy-idiot-talk.infracaninophile.co.uk X-Virus-Status: Clean X-Spam-Status: No, score=-1.8 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VERIFIED, SPF_FAIL, SUBJECT_FUZZY_TION, URIBL_RED autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on happy-idiot-talk.infracaninophile.co.uk Cc: "freebsd-questions@freebsd.org" Subject: Re: Should root partition be first partition? 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: Mon, 08 Feb 2010 14:30:29 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig427078F4DDD28AD6C2FF4AEA Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 08/02/2010 14:09, Peter Steele wrote: > I've set up a system with gpart and have the swap partition first > followed by root, var, and so on. This works fine but I've seen > documents that always have root first, then swap. Is there any reason > that root should be the first partition or can it follow swap space? The root partition should always be the 'a' partition, but it doesn't have to be the first in physical order on the disk (ie. starting at cylinder 0). So long as partitions don't overlap (with the historical exception of the 'c' partition, which should cover the whole drive) you can put them in any order and starting at any offset. You can even leave gaps between partitions if you want, but that is pretty crazy since it just wastes some of the available space. There have been quite a lot of recommendations on how to lay out a disk for best performance, based on the observation that disk access times vary depending on how far away the data is from the spindle, and the expected usage patterns for the partition. Like any such advice, it has tended to become less valid over time. Modern disks really don't have any physical meaning to the Cylinder/Head/Sector style addressing schemes[*] nowadays -- and you're pretty much bound to be using LBA style addressing anyhow. Also, machines nowadays have so much RAM that (a) swap is hardly ever used and (b) access to popular files is frequently answered out of VM caches rathe than needing disk IO. If your application is so demanding that you really need to squeeze out the last drop of IO performance, then you're much better off investing in fast SAS drives, a decent HW RAID controller with BBU and extra RAM. Otherwise, don't sweat it. Lay out the disks in a way that makes sense to you, and carry on with your life... Cheers, Matthew [*] But this still pops up in sysinstall, at the cost of much bewilderment for the uninitiated. --=20 Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard, Flat 3 Black Earth Consulting Ramsgate Kent, CT11 9PW Free and Open Source Solutions Tel: +44 (0)1843 580647 --------------enig427078F4DDD28AD6C2FF4AEA Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.14 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAktwH/8ACgkQ8Mjk52CukIym6QCeIMKx48YfPRoHx+ne5q3/saJv ZgQAnApQHvVEVCp5ex0XkwbgYsp+Xi0u =Qkm6 -----END PGP SIGNATURE----- --------------enig427078F4DDD28AD6C2FF4AEA--