From owner-freebsd-hackers@FreeBSD.ORG Sun Jun 1 16:05:54 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 BB54B2F1 for ; Sun, 1 Jun 2014 16:05:54 +0000 (UTC) Received: from mx1.scaleengine.net (beauharnois2.bhs1.scaleengine.net [142.4.218.15]) by mx1.freebsd.org (Postfix) with ESMTP id 96AA0286B for ; Sun, 1 Jun 2014 16:05:54 +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 2B83C7C26D for ; Sun, 1 Jun 2014 16:05:51 +0000 (UTC) Message-ID: <538B4F5F.2010700@freebsd.org> Date: Sun, 01 Jun 2014 12:05:51 -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> In-Reply-To: <538B4CEF.2030801@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: Sun, 01 Jun 2014 16:05:54 -0000 On 2014-06-01 11:55, Nathan Whitehorn wrote: > On 06/01/14 08:52, Steven Hartland wrote: >> ----- Original Message ----- From: "Mark Felder" >> >>> On May 31, 2014, at 20:57, Freddie Cash wrote: >>> >>>> There's a sysctl where you can set the minimum ashift for zfs. Then you >>>> never need to use gnop. >>>> >>>> I believe it's part of 10.0? >>> >>> I've not seen this yet. What we need is to port the ability to set >>> ashift at pool creation time: >>> >>> $ zpool create -o ashift=12 tank mirror disk1 disk2 mirror disk3 disk4 >>> >>> I believe the Linux zfs port has this functionality now, but we still >>> do not. >> >> We don't have that direct option yet but you can achieve the >> same thing by setting: vfs.zfs.min_auto_ashift=12 >> > Does anyone have any objections to me changing this default, right now, > today? > -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" The only other downside to 4k sectors is that you only get a history of 32 transaction groups instead of 128. Matt Ahrens says this isn't a big deal. I agree with changing the default to 12, a user making a new pool with 512b disks that is that worried about performance, can always shift the value back to 9. I will add this to the zfs section of the handbook, and make a specific note about this 512b issue. The 18,000 word ZFS section of the handbook should go live within a week or two. -- Allan Jude