Update: This is possible using EFI only installs, yay!
The Apple Mac Pro at work has four bays for 3.5″ hard drives. My plan was to have OS X on the main drive with Linux on a secondary drive for virtualised environments. Native Linux could run on drives in the other slots if necessary.
I installed OS X on the primary drive and install rEFIt to manage all operating systems. So far so good.
Next I installed Fedora 12 on the secondary drive, but no matter the installation layout (whether MBR or GPT) I couldn’t for the life of me get rEFIt to boot it.
The install would be detected and come up in the pretty menu, but booting it resulted in a completely black screen. Nothing I tried seemed to fix the issue (for some reason even a single drive with Linux and EFI only wouldn’t work).
At my wits end I decided to Google the issue and came across an entry in the Debian wiki which explains my issue:
rEFIt assumes that you have only one disk drive. If you try and install linux onto a secondary drive, you will probably have found that rEFIt lets you try and boot your newly-minted linux partition/drive, only for you to get a “Missing operating system” error message. This is actually a Syslinux error message. What happens is that rEFIt looks on the primary disk for an MBR record, fails to find one (obviously!), so sticks the syslinux MBR onto the primary disk, and tries to boot that.
So the problem appears to be with rEFIt Hopefully this will be fixed at some point, because being able to boot the OS from any drive on a Mac Pro would be oh, so handy.
In the mean time, I’ve installed Fedora on the same drive as OS X and will then use the other drives for virtualisation. I guess in theory putting /boot on a small partition on the primary drive with OS X might also work.