From owner-freebsd-current@freebsd.org Fri Mar 18 21:45:37 2016 Return-Path: Delivered-To: freebsd-current@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 1A693AD4F7F for ; Fri, 18 Mar 2016 21:45:37 +0000 (UTC) (envelope-from allanjude@freebsd.org) Received: from mx1.scaleengine.net (mx1.scaleengine.net [209.51.186.6]) by mx1.freebsd.org (Postfix) with ESMTP id D3D6110C2; Fri, 18 Mar 2016 21:45:36 +0000 (UTC) (envelope-from allanjude@freebsd.org) Received: from [192.168.1.10] (unknown [192.168.1.10]) (Authenticated sender: allanjude.freebsd@scaleengine.com) by mx1.scaleengine.net (Postfix) with ESMTPSA id 62CADD4FB; Fri, 18 Mar 2016 21:45:30 +0000 (UTC) Subject: Re: boot loaders got fatter in the last few days To: Freddie Cash , cem@freebsd.org References: <56EC2DD3.6050803@madpilot.net> <56EC34CE.1000002@freebsd.org> Cc: freebsd-current From: Allan Jude Message-ID: <56EC76F3.9030906@freebsd.org> Date: Fri, 18 Mar 2016 17:45:23 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Mar 2016 21:45:37 -0000 On 2016-03-18 17:41, Freddie Cash wrote: > > On Fri, Mar 18, 2016 at 10:39 AM, Conrad Meyer > wrote: > > On Fri, Mar 18, 2016 at 10:03 AM, Allan Jude > wrote: > > On 2016-03-18 12:33, Guido Falsi wrote: > >> > >> Hi, > >> > >> I have just update one of my machines and noticed the booloaders > files > >> got quite fat in the last few days, some by a big margin. > >> > >> on an updated machine(r296993): > >> > >> -r--r--r-- 1 root wheel 85794 Mar 18 16:47 /boot/gptboot > >> > >> from a machine I still have not updated(r296719): > >> > >> -r--r--r-- 1 root wheel 16059 Mar 13 21:01 /boot/gptboot > > So the loader grew 70 kB. How big are your disks? > > >> I noticed because mu gpt boot partition is 64K and gptzfsboot just > >> passed 100K. > > > > This is a side effect of the loader gaining the ability to boot > from GELI > > encrypted partitions. > > > > ... > > > > Maybe we should be putting the GELI enabled boot blocks in a > different > > filename? I generally wanted to avoid creating a new version of each > > bootcode with GELI support. > > > I think we should just suggest that boot partitions be much larger > than 64kB (1MB is still <0.1% of any disk sold today) and not worry > about it too much. Embedded applications can disable GELI loader > support to save a few bytes. > > > ​The boot partition doesn't necessarily need ​ > ​to be 1 MB (and can't due to some issues with the assembler used right > now, or something like that). We just need to make sure people have > slack space in their partition table to expand into in the future. > > Using "-a 1M" in your gpart command to create your first data partition > gives you that slack space. > > gpart create -s gpt ada0 > gpart add -t freebsd-boot -s 256K -l boot ada0 > gpart add -t freebsd-ufs -s 10G -l root -a 1M ada0 > > That leaves ~756 KB of free space between the end of the boot partition > and the start of the first data partition. Increasing the size of the > boot partition in the future is as easy as (no formatting of disks > required): > > gpart delete -i 1 ada0 > gpart add -t freebsd-boot -s 512K -l boot ada0 > gpart bootcode -b ... -p ... ada0 > > It's a handy pattern I've gotten used to over the years, ever since the > first 4K sector harddrives were advertised (as alignment of filesystems > was/is *very* important)​. > > Even on disks that will be used solely for ZFS I've taken to creating > GPT partitions starting at 1 MB. And it's saved me from having to > reformat disks when moving from a separate root filesystem (no USB > sticks) to root-on-ZFS as there was 1 MB of free space at the start of > every disk for creating boot partitions. :) > > -- > Freddie Cash > fjwcash@gmail.com This also has the handy side effect of allowing you to switch to booting with UEFI, which currently uses an 800kb fat file system -- Allan Jude