[CentOS] Module loading order during install

Tue Apr 19 14:22:13 UTC 2005
Aleksandar Milivojevic <amilivojevic at pbl.ca>

Joshua Baker-LePain wrote:
> Is there a way in a kickstart install to affect the order in which modules 
> get loaded?  I want to load 3w-xxxx before 3w-9xxx so that my OS mirror 
> drives take their proper place as sda and sdb, but centos-4 wants to load 
> 3x-9xxx first, making my (unbootable) big arrays the first two drives.  In 
> this configuration, it seems that even trying to install grub to /dev/sdc 
> fails.  Ideas?  Thanks.

The order of devices should be irrelevant.  It is more or less cosmetic 
issue.  It is more than possible that order will be different during 
installation, and once machine is booted up from the disk.  Once the 
machine is booted from the disk, it will most likely be the order they 
appear in /etc/modprobe.conf.  On my Adaptec I2O RAID controler, the 
order disks are detected and assigned names is totally random.  Changes 
on every boot.  Interestingly, Adaptec BIOS detects disks always in same 
order, so does PC BIOS when it takes over once Adaptec BIOS 
initialization is done.  It's only i2o_block device driver under Linux 
that has this random behaviour.

The grub installation from Anaconda has some issues on 
RHEL4/CentOS4/FC3.  Check archives for this list and Fedora mailing 
list.  Basically, if Anaconda fails to install it, boot into rescue mode 
after the system installation is complete and install Grub by hand 
(chroot, grub-install).  Alternatvie is to use LILO if you are more 
familiar with it then with Grub.  LILO can be selected as option if you 
are doing kickstart installation.  Not sure if you can select it from 
GUI?  Anyhow, you can always install it from rescue mode.

Once you install the system, you could (probably) attempt to use udev 
configuration files to assign specific device names to specific devices. 
  Check /usr/share/doc/udev-039/writing_udev_rules/index.html file (part 
of udev package) on info how to do it (OK, you'll have to have some 
running CentOS4 or Fedora system, first).

There are also some tricks to avoid using device names in /etc/fstab. 
The best one is to use LVM.  Then it is irrelevant how the kernel calls 
your devices.  You are always accessing them using fixed LVM names. 
Using LVM is good idea anyhow, IMO.

LVM doesn't work for boot partition (which is usually either / or /boot, 
depending on if you created separate partition for /boot or not). 
However, for that one you can always use file system label to reference 
it from /etc/fstab and lilo.conf (maybe also grub.conf?).  Another neat 
trick for boot partition is placing it on software RAID.  Software RAID 
device names (/dev/md*) are also more or less fixed.

Aleksandar Milivojevic <amilivojevic at pbl.ca>    Pollard Banknote Limited
Systems Administrator                           1499 Buffalo Place
Tel: (204) 474-2323 ext 276                     Winnipeg, MB  R3T 1L7