Re: how to tell when biosboot partition is needed?

On Fri, Aug 10, 2012 at 09:57:26PM +0200, Richard Neuboeck wrote:
> Hi List,
> 
> I'm in the same predicament as Steve. My manual test installs of
> Fedora 17 result in msdos and gpt partition table labels. Since I'm
> using kickstart and a pre install script to partition the disc I would
> also like to find a way to determine if a biosboot partition is
> necessary or not.
> 
> The only sure reason to install a biosboot partition I could find was
> a disc >= 3TB.
> 
> The UEFI test system I'm using definitely has UEFI enabled and since
> the disc has 3TB should use EFI. But I couldn't find efi in sysfs like
> anaconda tries to do to determine if it's an EFI capable system.
> However this system gets a gpt label in my tests. But I don't know how
> anaconda comes to that conclusion.

I never heard/found any tips or other ideas, and I couldn't follow how
Anaconda decides what to do either; so I simply started grep'ing around
during a live %pre session to see what I could find.

I came across /tmp/storage.log , which among many other things had a line
like this:

    storage: registered device format class BIOSBoot as biosboot

which was about the only reference I could find to "biosboot" in the
live Kickstart session.  I was thinking there might be something in
/proc/ or /sys/ or thereabouts, but found nothing I could make use of.

In any case, my %pre disk partitioning script looks for that string, and
if found then it adds an entry for a biosboot partition similar to:

    part biosboot --size 1 --fstype biosboot

This method has the advantage of being independent of disk size, and
also doesn't perform additional partitioning actions on older releases
where /tmp/storage.log reports nothing about biosboot.  So I can keep
using the same %pre script to partition old & new Fedoras, CentOS, etc.

The obvious peril is Fedora may change/move/etc. the string in some future
version of Anaconda, so I still occasionally keep an eye out for something
a bit more programmatic/definitive; we'll see how well it holds up.

Cheers,
sr.


> So right now I'm only relying on the disk size to choose the partition
> layout in my preinstall script.
> 
> Any pointers where I can find more details or information on how to
> make an educated guess on how to partition would be very welcome.
> 
> Thanks!
> Richard
> 
> 
> On 09.06.12 01:00, Steve Rikli wrote:
> > Is there some programmatic way within Kickstart %pre to determine
> > if a "biosboot" partition is needed, or at least if it is an
> > available option/fstype?
> > 
> > Like many folks, we create a "/tmp/partitions.inc" sort of
> > %include file in %pre, to partition the disk.
> > 
> > Starting in Fedora16 a "part biosboot ..." partition is required, 
> > and ideally we'd like to be able to use the same %pre script to 
> > setup partitions on all the different Linux versions we need.
> > 
> > We would be okay with "wasting" 1MB and always creating a biosboot 
> > partition for any Linux, but it's not a supported type prior to 
> > Fedora16, so that isn't an option.
> > 
> > Thanks, sr.
> >