Re: /boot/efi size, 260MiB minimum for FAT32 ESP) -- WAS: /boot size

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Apr 15, 2016 at 6:16 PM, Bryan Smith <b.j.smith@xxxxxxxx> wrote:
> Ross Smith wrote:
>> I don't think it will be an issue.  I've already been bitten by this with a
>> ~1300 efi booted desktops and would welcome the updated
>> configuration.
>
> Speaking of which ...
>
> Q:  Shouldn't we be using 260MiB FAT32 as a minimum EFI System
> Partition (ESP) size going forward, especially as 4KiB logical blocks
> become regular?

Well, mkdosfs defaults to FAT16 and 4K cluster size on a 200M
partition, so that should continue to work, even though the UEFI spec
says to use FAT32 on system partitions. So chances are doing nothing
isn't going to break anything.

In practice, both Windows and OS X use FAT32, but they also use
cluster sizes smaller than 4K. Presumably both of them will transition
to 256+M EFI system partitions, rather than use FAT16.



>
>
>  o  Just some history (detail) ...
>
> - For NT6.0 (Vista), Microsoft recommended (and its installers
> created) a 200MiB FAT32 ESP
> - This size has seemingly "stuck" with most distros, even though ...
> - For NT6.1+ (7+/2008+), Microsoft recommended (and its installers
> created) a 100MiB FAT32 ESP
> However ...
> - If the logical block size is 4KiB, the smallest FAT32 file system is 260MiB
> Although ...
> - The ESP can be FAT16 (just like good'ole ARC) instead of FAT32
> - Every ESP I've used, including Windows 7 and 8 x64, seems to install
> fine on a FAT32 ESP
>
> Hence why I'm bringing it up.  Just curious if there has been much
> discussion on this.  I did some google searches on the archives and
> couldn't find anything.

https://bugzilla.redhat.com/show_bug.cgi?id=1046577
https://www.freedesktop.org/wiki/Specifications/BootLoaderSpec/
https://www.freedesktop.org/wiki/MatthewGarrett/BootLoaderSpec/
and maybe
https://www.redhat.com/archives/anaconda-devel-list/2014-July/msg00002.html


Ideally there'd be an -E flag for mkdosfs to deal with this. The UEFI
spec says firmware is expected to support FAT32, FAT16, and FAT12 so
it probably doesn't matter that the spec also says the system
partition (non-removable) should be FAT32, where only removables get
FAT16 or FAT12. The other thing -E would make possible is ensuring the
proper invariant "EFI file system" is what's actually being created,
rather than pure FAT.

-- 
Chris Murphy

_______________________________________________
Anaconda-devel-list mailing list
Anaconda-devel-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/anaconda-devel-list



[Index of Archives]     [Kickstart]     [Fedora Users]     [Fedora Legacy List]     [Fedora Maintainers]     [Fedora Desktop]     [Fedora SELinux]     [Big List of Linux Books]     [Yosemite News]     [Yosemite Photos]     [KDE Users]     [Fedora Tools]
  Powered by Linux