Install question #2 - disk order and video mode

[Chris Snook]

Timothy Murphy wrote:
> Chris Snook wrote:
> 
>> Bill Davidsen wrote:
>>> The FC8 install seems to assign drive identifiers in some random order
>>> instead of BIOS order. I thought that was fixed back around 2.6.17, but
>>> it certainly isn't the case AFAIK, if I boot the rescue CD I get one set
>>> of assignments (not BIOS order), and if I boot I get another. Needless
>>> to say this makes getting a bootable install nearly impossible.
>> Device scanning is asynchronous now, and drives may come up in *any*
>> order, potentially changing even across reboots even with no changes to
>> software or hardware.  This is why we use labels and uuids.
> 
> Would that help when installing from CD, as Bill seemed to be asking about?
> 

The installer assigns labels to everything that isn't on LVM, so 
everything should mount just fine.  If you add stuff to /etc/fstab 
post-install that isn't on LVM and isn't labeled, you could have problems.

The only way the installer can screw up without user intervention is if 
it misconfigures grub.  Since the bios device ordering is guaranteed to 
be different from install to normal boot under these circumstances, the 
only guaranteed correct way to fix this is to use firmware, bootloaders, 
and partition tables that support partition names, as is the case with 
EFI supporting GPT.  Unfortunately, in the BIOS/MSDOS world, we're stuck 
doing ugly hacks (like latefcload, for fibre channel users) or fixing it 
manually post-install.

The good news is that since BIOSes weren't designed to choose from 
thousands of boot devices, their ordering is deterministic, so you only 
have to fix the bootloader config once.

There are probably more and better ugly hacks we can do to make this 
suck less, but fundamentally this is a limitation of the BIOS.

-- Chris