From owner-freebsd-hackers@FreeBSD.ORG Mon Jun 2 12:38:20 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 59D7DDE4 for ; Mon, 2 Jun 2014 12:38:20 +0000 (UTC) Received: from mx1.scaleengine.net (beauharnois2.bhs1.scaleengine.net [142.4.218.15]) by mx1.freebsd.org (Postfix) with ESMTP id 33AEA204E for ; Mon, 2 Jun 2014 12:38:19 +0000 (UTC) Received: from [192.168.1.70] (d206-75-77-44.abhsia.telus.net [206.75.77.44]) (Authenticated sender: allanjude.freebsd@scaleengine.com) by mx1.scaleengine.net (Postfix) with ESMTPSA id 15B4D7CAC9 for ; Mon, 2 Jun 2014 12:38:12 +0000 (UTC) Message-ID: <538C7035.5080700@freebsd.org> Date: Mon, 02 Jun 2014 08:38:13 -0400 From: Allan Jude User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: freebsd-hackers@freebsd.org Subject: Re: fdisk(8) vs gpart(8), and gnop References: <20140601004242.GA97224@bewilderbeast.blackhelicopters.org> <3D6974D83AE9495E890D9F3CA654FA94@multiplay.co.uk> <538B4CEF.2030801@freebsd.org> <1DB2D63312CE439A96B23EAADFA9436E@multiplay.co.uk> <538B4FD7.4090000@freebsd.org> In-Reply-To: <538B4FD7.4090000@freebsd.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit 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 12:38:20 -0000 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 > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" 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? -- Allan Jude