Date: Fri, 18 Mar 2016 14:41:58 -0700 From: Freddie Cash <fjwcash@gmail.com> To: cem@freebsd.org Cc: Allan Jude <allanjude@freebsd.org>, freebsd-current <freebsd-current@freebsd.org> Subject: Re: boot loaders got fatter in the last few days Message-ID: <CAOjFWZ44sJhggWvQgJQhrPQ=xecTGnAkmUxvSKbgELzXcDTUMg@mail.gmail.com> In-Reply-To: <CAG6CVpUxrmsLg=UROqqo_SKmqrqJMTtqyrij63nxigb5eB=WPA@mail.gmail.com> References: <56EC2DD3.6050803@madpilot.net> <56EC34CE.1000002@freebsd.org> <CAG6CVpUxrmsLg=UROqqo_SKmqrqJMTtqyrij63nxigb5eB=WPA@mail.gmail.com>
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On Fri, Mar 18, 2016 at 10:39 AM, Conrad Meyer <cem@freebsd.org> wrote: > On Fri, Mar 18, 2016 at 10:03 AM, Allan Jude <allanjude@freebsd.org> > 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 GE= LI > > 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. > =E2=80=8BThe boot partition doesn't necessarily need =E2=80=8B =E2=80=8Bto be 1 MB (and can't due to some issues with the assembler used r= ight 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)=E2=80=8B. 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. :) --=20 Freddie Cash fjwcash@gmail.com
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