I've got an answer from David Lehman how the decision process for the usage of biosboot works in anaconda: Here is the entire decision tree: - did the system boot in EFI mode or BIOS mode? - EFI - use gpt and never make biosboot - BIOS - is the disk larger than the max for msdos (2TB)? - yes - use gpt and ensure there's a biosboot partition - no - use msdos So in my preinstall script I check for EFI capabilities and the disk size: # get disk size in GB DISKSIZE=`parted -sm /dev/$DEV unit GB print | grep -e "$DEV" | cut -d: -f2 | sed -e 's/GB$//'` if [ -e /sys/firmware/efi -o $DISKSIZE -gt 2100 ] then # bios boot partition necessary echo "part biosboot --fstype=biosboot --size=1 --ondisk=$DEV" >> $INCFILE fi HTH Richard On 11.08.12 11:36, Richard Neuboeck wrote: > Thanks! > > I mulled over the sources but didn't find the indicators for the final > selection of gpt over msdos as partition table label. > > I'm not giving up yet :-) > Richard > > On 10.08.12 23:41, Steve Rikli wrote: >> 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. >>>> >> >> _______________________________________________ >> Kickstart-list mailing list >> Kickstart-list@xxxxxxxxxx >> https://www.redhat.com/mailman/listinfo/kickstart-list >> > > _______________________________________________ > Kickstart-list mailing list > Kickstart-list@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/kickstart-list > _______________________________________________ Kickstart-list mailing list Kickstart-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/kickstart-list