From owner-freebsd-questions@freebsd.org Sun Sep 11 03:40:52 2016 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 216DEBD5AE1 for ; Sun, 11 Sep 2016 03:40:52 +0000 (UTC) (envelope-from perryh@pluto.rain.com) Received: from agora.rdrop.com (agora.rdrop.com [IPv6:2607:f678:1010::34]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 06D1E1EE3 for ; Sun, 11 Sep 2016 03:40:52 +0000 (UTC) (envelope-from perryh@pluto.rain.com) Received: from agora.rdrop.com (66@localhost [127.0.0.1]) by agora.rdrop.com (8.13.1/8.12.7) with ESMTP id u8B3eplb005984 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Sat, 10 Sep 2016 20:40:51 -0700 (PDT) (envelope-from perryh@pluto.rain.com) Received: (from uucp@localhost) by agora.rdrop.com (8.13.1/8.14.2/Submit) with UUCP id u8B3eonb005983; Sat, 10 Sep 2016 20:40:50 -0700 (PDT) (envelope-from perryh@pluto.rain.com) Received: from fbsd81 by pluto.rain.com (4.1/SMI-4.1-pluto-M2060407) id AA10765; Sat, 10 Sep 16 20:38:25 PDT Date: Sat, 10 Sep 2016 20:38:34 -0700 From: perryh@pluto.rain.com (Perry Hutchison) To: wblock@wonkity.com Cc: brandon.wandersee@gmail.com, freebsd-questions@freebsd.org Subject: Re: "gpart add" falsely claiming "No space left on device" Message-Id: <57d4d1ba.8U9+KrRH1rRsodn4%perryh@pluto.rain.com> References: <57ce6e64.EITkODjuwy6pZ4L+%perryh@pluto.rain.com> <57cf9b95.Zj/JGHeshaKL6Zr5%perryh@pluto.rain.com> <57d0f29b.3QNvCze7LJDzs0SU%perryh@pluto.rain.com> <86wpimm6om.fsf@WorkBox.Home> <57d276f6.CwaoGNki0kQYiZns%perryh@pluto.rain.com> In-Reply-To: User-Agent: nail 11.25 7/29/05 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 Sep 2016 03:40:52 -0000 Warren Block wrote: > Support for 8.1 ended over four years ago. Improvements to man > pages are not MFCed back to unsupported releases. Nor would it matter (in this case) if they were, since I'm running 8.1 (not following 8-STABLE). > > Alignment to 4k makes sense if the physical sector size is 4k (as > > is often the case with newer disk drives) -- but 1M? Seems a bit > > much, which is why it would be useful for that page to include a > > more detailed explanation. > > 1M is a useful value for several reasons. A partition aligned with 1M > is aligned with all the smaller values. It also better fits with the > larger internal block sizes used by SSDs and other flash devices. > > Starting the first data partition at 1M is a de facto standard and > provides a little additional insurance that some rock-stupid > partitioning tool will see the partition and not destroy it. > > At most, aligning to 1M wastes less than one meg of space. Not one gig, > one meg. On UEFI systems, you can even use that small amount of space > for an EFI partition. Hopefully some of this explanation will find its way into that disksetup.html page :)