A.4. Set up the boot loader
In order to actually use the initrd at boot time, the boot-loader must know the location
of the initrd so it can tell the kernel where to load it from. There are also some other changes
that the boot loader needs to know about in order to successfully mount your EVMS
volume as the root file system. The procedure is slightly different for LILO and GRUB, the
two main boot loaders used with Linux.
A.4.1. LILO procedure
LILO uses the file /etc/lilo.conf as its configuration file. Edit
the file with a text editor. If you have not already done so, add an image section
for the kernel you will be using with EVMS. The section should look something like this:
image = /boot/vmlinuz-2.4.20 # Replace with your kernel image
label = 2.4.20 #Any label you'd like to use
read-only
initrd = /boot/initrd-evms.gz # The compressed initrd you just created
append = "ramdisk=16384 root=/dev/evms/Root" |
The last line (beginning with "append") in this section is very important. The line specifies
parameters that are passed to the kernel command line. The "ramdisk" option
overrides the default ramdisk size. This value is in kilobytes and needs to be
at least as big as the initrd image you created in step Section A.3.1. Thus, if your initrd
image is 20 MB, you need to set this value to 20 * 1024 = 20480.
The "root" option in the "append" line is not only a parameter to the kernel
but also an indicator to the linuxrc script (Section A.3.9) so it can determine the name of
your root file system and use it to tell the kernel the actual root device after the
volumes have been activated. Obviously, you should set this option to the actual
name of your root volume.
After updating /etc/lilo.conf, run lilo to install the boot-loader.
A.4.2. GRUB procedure
GRUB uses the file /boot/grub/menu.lst as its configuration file.
Edit this file with a text editor. If you have not already, add a menu item for the kernel
you will be using with EVMS. The menu item should look something like this:
title 2.4.20 # Any label you'd like to use
kernel (hd0,0)/vmlinuz-2.4.20 root=/dev/evms/Root ramdisk=16384
# Replace with the name of your kernel image.
# See the Grub documentation for which (hdx,y)
# value to use.
initrd (hd0,0)/initrd-evms.gz # The compressed initrd image you just created |
The extra information after the kernel image name is very important.
These are parameters that are passed to the kernel command line.
The "ramdisk" option
overrides the default ramdisk size. This value is in kilobytes and needs to be
at least as big as the initrd image you created in Section A.3.1. Thus, if your initrd
image is 20 MB, you need to set this value to 20 * 1024 = 20480.
The "root" option in the "kernel" line is not only a parameter to the kernel
but also an indicator to the linuxrc script (Section A.3.9) so it can determine the name of
your root file system and use it to tell the kernel the actual root device after the
volumes have been activated. Obviously, you should set this option to the actual
name of your root volume.
