From owner-freebsd-hackers@FreeBSD.ORG Thu May 24 12:22:17 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 51CFB1065670 for ; Thu, 24 May 2012 12:22:17 +0000 (UTC) (envelope-from aduane@juniper.net) Received: from exprod7og115.obsmtp.com (exprod7og115.obsmtp.com [64.18.2.217]) by mx1.freebsd.org (Postfix) with ESMTP id 2C26A8FC0C for ; Thu, 24 May 2012 12:22:07 +0000 (UTC) Received: from P-EMHUB01-HQ.jnpr.net ([66.129.224.36]) (using TLSv1) by exprod7ob115.postini.com ([64.18.6.12]) with SMTP ID DSNKT74n7k+WpdOsKzxO0vSMYKYP2Wu1XNOM@postini.com; Thu, 24 May 2012 05:22:16 PDT Received: from p-emfe01-wf.jnpr.net (172.28.145.24) by P-EMHUB01-HQ.jnpr.net (172.24.192.35) with Microsoft SMTP Server (TLS) id 8.3.213.0; Thu, 24 May 2012 05:16:27 -0700 Received: from EMBX01-WF.jnpr.net ([fe80::1914:3299:33d9:e43b]) by p-emfe01-wf.jnpr.net ([fe80::d0d1:653d:5b91:a123%11]) with mapi; Thu, 24 May 2012 08:16:26 -0400 From: Andrew Duane To: Tim Kientzle , Warren Block Date: Thu, 24 May 2012 08:16:26 -0400 Thread-Topic: proper newfs options for SSD disk Thread-Index: Ac05aL8GJV1xscvwQaOw9bi6X7F8uwAPdA/Q Message-ID: References: <4fb7dfd6.736a980a.186d.ffff902f@mx.google.com> <20120519180901.GA1264@tiny> <4fb7e819.6968700a.7a7f.ffff9153@mx.google.com> <20120522061734.GA1210@tiny> <20120522134846.GA2274@tiny> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: "freebsd-hackers@freebsd.org" , Apitz , Matthias Subject: RE: proper newfs options for SSD disk X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 May 2012 12:22:17 -0000 > -----Original Message----- > From: owner-freebsd-hackers@freebsd.org [mailto:owner-freebsd-hackers@fre= ebsd.org] On Behalf Of Tim Kientzle > Sent: Thursday, May 24, 2012 12:49 AM > To: Warren Block > Cc: freebsd-hackers@freebsd.org; Matthias Apitz > Subject: Re: proper newfs options for SSD disk >=20 > GPart's alignment option doesn't work for MBR slices. > It rounds to the requested alignment, and then rounds again > to the track size, which defaults to 63 sectors. >=20 > I'm not convinced this is a bug in the design of MBR. I don't > think anything in the MBR design requires that partitions > be track-aligned. >=20 > Tim It really doesn't. This is old school thinking based around minimizing seek= and rotation time on slow multiplatter HDDs. It also helped the redundant = superblock layout scheme of UFS make that spiral striping down a set of dis= k platters. My bet is no one has ever bothered to rethink this in the 25 ye= ars since.... ................................... Andrew Duane Juniper Networks +1 978-589-0551 (o) +1 603-770-7088 (m) aduane@juniper.net =A0