On Thu, 2011-08-25 at 16:17 -0600, Andrew McNabb wrote: > While installing Fedora 16 Alpha, I ran into some problems that turned > out to be caused by the installer formatting with a GPT rather than an > MBR partition table. > > I would like to understand the change and its implications, and I have > unsuccessfully tried to track down more information. I haven't been > able to find anything in the Fedora 16 Alpha Release Notes or the Grub2 > feature page. The only definitive reference I've been able to find is > the comment "x86 uses GPT disklabels by default on all machines, even > non-EFI" on the Anaconda/Changes wiki page. > > There seem to be some complications associated with the change. For > example, Windows can only support GPT on UEFI machines, so dual-booting > appears to be unsupported (I could not find an option for MBR partition > tables in the installer). > > Where should I look for more information? Thanks. To boot to a GPT disk from BIOS (rather than EFI) you need a BIOS boot partition. If you use one of the automatic partitioning methods, rather than manual partitioning, F16's installer will create one for you. If you choose manual partitioning on a BIOS system and don't create a BIOS boot partition, anaconda will pop up a (somewhat cryptic) warning.

If you're installing alongside an existing copy of Windows I believe anaconda ought to leave the disk label alone (MSDOS) anyway, though I'm not sure we've tested that. It should only write a new one if you're blowing away any existing partitions on the disk, I think. (IMBW on this one).

-- Adam Williamson Fedora QA Community Monkey IRC: adamw | Twitter: AdamW_Fedora | identi.ca: adamwfedora http://www.happyassassin.net

On Thu, Aug 25, 2011 at 07:17:58PM -0500, David Lehman wrote: > > It's also true that if you create an msdos/mbr partition table on your > disk prior to installation and then choose any option except for "Use > All Space" (or "clearpart --all" in kickstart) anaconda will not destroy > your existing partition table. But if you first install Fedora to a clean disk, then it will never be possible to later install Windows, right?

To boot to a GPT disk from BIOS (rather than EFI) you need a BIOS boot partition. If you use one of the automatic partitioning methods, rather than manual partitioning, F16's installer will create one for you. If you choose manual partitioning on a BIOS system and don't create a BIOS boot partition, anaconda will pop up a (somewhat cryptic) warning.

On Fri, Aug 26, 2011 at 04:29:55PM +0200, Karel Zak wrote: > > Windows and GPT FAQ: > > Q. Can Windows 7, Windows Vista, and Windows Server 2008 read, write, > and boot from GPT disks? > > A. Yes, all versions can use GPT partitioned disks for data. > Booting is only supported for 64-bit editions on UEFI-based > systems. > > http://msdn.microsoft.com/en-us/windows/hardware/gg463525.aspx

I don't know for sure, but this may be a case where progress is more important than compatibility. In any case, it would be comforting to have this issue documented in the Fedora 16 Release Notes.

btw, I just installed F16 on an EFI machine and got Grub Legacy. Are there any major problems with Grub 2's EFI support?

From a brief conversation I had earlier this week, yes there are. The

On Sat, Aug 27, 2011 at 04:04:30AM +0200, Lars Seipel wrote: > On Friday, August 26, 2011 04:58:22 PM Al Dunsmuir wrote: > > On systems where 32-bit is XP is running, one by definition is running > > with a disk of 2 TB or less. Fedora installation must by default do > > the right thing. We need to agree on what that happens to be. > > On systems with legacy operating systems installed Fedora does not touch the > partition table at all. On all other systems GPT is the way to go I'd say... > In F16 is it still possible to force creation of MSDOS partition table without GPT using a kickstart script ?

On Fri, 2011-10-14 at 22:44 +0300, Pasi Kärkkäinen wrote: > On Fri, Oct 14, 2011 at 09:53:53PM +0300, Pasi Kärkkäinen wrote: > > On Sat, Aug 27, 2011 at 04:04:30AM +0200, Lars Seipel wrote: > > > On Friday, August 26, 2011 04:58:22 PM Al Dunsmuir wrote: > > > > On systems where 32-bit is XP is running, one by definition is running > > > > with a disk of 2 TB or less. Fedora installation must by default do > > > > the right thing. We need to agree on what that happens to be. > > > > > > On systems with legacy operating systems installed Fedora does not touch the > > > partition table at all. On all other systems GPT is the way to go I'd say... > > > > > > > In F16 is it still possible to force creation of MSDOS partition table > > without GPT using a kickstart script ? > > > > Or with some boot/cmdline option? > > Afaik for example rhel5 Xen pygrub has issues with GPT, > and it'd be good to be able to install F16 domUs on rhel5 Xen > by forcing creation of msdos partition table.. As of Final TC1 (anaconda 16.21) this should be possible by passing 'nogpt' as a kernel parameter to the installer.