Ubuntu Fedora partition identifiers UUID problems

Georgina Joyce gena at mga.demon.co.uk
Mon May 12 13:39:58 EDT 2008


Hi All


I've had a difficult time these past couple of days. Because I installed
more than one distribution on a disk. Thus I'll note my observations
here so that others don't have the same difficulties I've had finding
solutions.


Ubuntu Hardy does not observe the bios settings on machines with IDE and
SATA drives. Difficulties occur if the SATA disk is set as the primary
active bootable disk. Ubuntu Hardy puts the IDE as /dev/sda and the SATA
as /dev/sdb. When you boot the machine having gone through the 7 steps
of the install process. If they are booted according to the bios
configuration problems occur. Because the order of the drives are
different to that of the installation environment.


The problem is that Ubuntu and Fedora are using the UUID definitions
in /etc/fstab. Which make it very difficult to trace where the problems
are to be found. The Ubuntu forums talk of a utility called vol_id buts
that's not any use when you need some kind of rescue disk to regain
access to the machine and drives. The fix is to use blkid, see man blkid
for details. Without any arguments blkid will print to stdout volume
ID's on the system. Which can be cross referenced with the /etc/fstab.
It might also be necessary to reinstall grub but not from the Ubuntu CD
because of this drive organisation problem.


The subject of UUID can be found on the Fedora and Ubuntu forums. Many
contributors have complained about the ugliness of these 32 bit codes as
partition identifiers. Any resizing or reorganisation of partitions will
cause users problems if their distribution uses UUID as the partition
identifiers. 


I missed the advanced button on the seventh step which reinstalled grub.
So that's two reasons for thumbs down for Ubuntu. Therefore, anyone
installing Ubuntu on a system with another existing distribution, ensure
that you press the advanced button on the seventh step and select not to
install a boot loader.

Gena

-- 
Gena

http://www.ready2golinux.com

M0EBP





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