VirtualBox - Guest Addition Installation

1. Log into the VM as the root user and add the "divider=10" option to the kernel boot options in "/etc/grub.conf" file to reduce the idle CPU load. The entry should look something like this.

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/VolGroup00/LogVol00
#          initrd /initrd-version.img
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Enterprise Linux (2.6.18-194.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-194.el5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet divider=10
        initrd /initrd-2.6.18-194.el5.img

2. From VirtualBox Menu Bar, select Devices -> Install Guest Additions
3. Double click the CD-ROM to mount Guest Additions
4. Open a terminal, go to Guest Addition location and run as below:
     sh ./VBoxLinuxAdditions.run
5. Reboot Linux