From owner-freebsd-hackers@FreeBSD.ORG Mon Jun 2 17:03:34 2014 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 001ED93E; Mon, 2 Jun 2014 17:03:33 +0000 (UTC) Received: from smtp1.multiplay.co.uk (smtp1.multiplay.co.uk [85.236.96.35]) by mx1.freebsd.org (Postfix) with ESMTP id B69882CF3; Mon, 2 Jun 2014 17:03:33 +0000 (UTC) Received: by smtp1.multiplay.co.uk (Postfix, from userid 65534) id 2E5DB20E7088B; Mon, 2 Jun 2014 17:03:26 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.multiplay.co.uk X-Spam-Level: ** X-Spam-Status: No, score=2.3 required=8.0 tests=AWL,BAYES_00,DOS_OE_TO_MX, FSL_HELO_NON_FQDN_1,HELO_NO_DOMAIN,RDNS_DYNAMIC,STOX_REPLY_TYPE autolearn=no version=3.3.1 Received: from r2d2 (82-69-141-170.dsl.in-addr.zen.co.uk [82.69.141.170]) by smtp1.multiplay.co.uk (Postfix) with ESMTPS id F3B9020E70886; Mon, 2 Jun 2014 17:03:20 +0000 (UTC) Message-ID: From: "Steven Hartland" To: "Allan Jude" , References: <20140601004242.GA97224@bewilderbeast.blackhelicopters.org> <3D6974D83AE9495E890D9F3CA654FA94@multiplay.co.uk> <538B4CEF.2030801@freebsd.org> <1DB2D63312CE439A96B23EAADFA9436E@multiplay.co.uk> <538B4FD7.4090000@freebsd.org> <538C7035.5080700@freebsd.org> Subject: Re: fdisk(8) vs gpart(8), and gnop Date: Mon, 2 Jun 2014 18:03:26 +0100 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Jun 2014 17:03:34 -0000 ----- Original Message ----- From: "Allan Jude" > On 2014-06-01 12:07, Nathan Whitehorn wrote: >> >> So the discussion here is related to what to do about the installer. The >> current ZFS component unconditionally creates gnops all over the place >> to set ashift to 4k. That's across the board worse: it has exactly the >> performance impact of changing the default of this sysctl (whatever that >> is), it can't easily be overridden (which the sysctl can), and it's a >> horrible hack to boot. There are a few options: >> >> 1. Change the default of vfs.zfs.min_auto_ashift >> 2. Have the same effect but in a vastly worse way by adjusting the >> installer to create gnops >> 3. Have ZFS choose by itself and decide to do that permanently. >> >> Our ATA code is good about reporting block sizes now, so (3) isn't a big >> issue except for the mixed-pool case, which is a huge PITA. >> >> We need to choose one of these. I favor (1). >> -Nathan > > I favour 1 as well. > > Note: the current ZFS installer script forces 4k with gnop if the option > is turned on (it is by default), but you can have it not use gnop. > > But yes, this new sysctl (it is very new), is great. Will it be MFC'd in > time for 9.3? I MFC'ed to stable/10 and stable/9 ~2 weeks so yes :)