Ubuntu boot time

Ubuntu 7.04 (Feisty Fawn) uses a disk-cache to speed up the boot time. On startup it will preload a lot of files in an optimized reading pattern to reduce the startup time. As the distribution knows nothing about your system it ships with a rather generic Pattern.

To get a nice listing of starting processes, we first install bootchart.

apt-get install bootchart

This will rebuild your initrd. Now Reboot the system and you will find a nice png image in /var/log/bootchart

Wow. Booting takes 1:14 minutes!

We will now profile our boot process. This will take longer than your normal boot but trust me, it's worth your time.

Reboot your system. When Grup starts up, edit your boot process.

After the BIOS finishes  there will be a line like "Grub starts in ... seconds". Hit ESC.

Now you will see the grub menu. Use the arrow keys to select your default kernel (Normally that's the first entry, if you changed that you should know which kernel you are using).

Hit "e" to edit this entry. You will see something like this

title           Ubuntu, kernel 2.6.20-15-generic
root            (hd0,4)
kernel          /vmlinuz-2.6.20-15-generic root=/dev/sda6 ro nosplash vga=0x31b
initrd          /initrd.img-2.6.20-15-generic

Select the line with the kernel. Hit 'e' again to edit this line. Go to the end of the line, append "profile". Hit Enter. Hit "b"

Now the system will boot.

During this Boot the system will record all files read during startup. When finished it will write a list in

/etc/readahead/boot

Check the timestamp of this file. When finished, Just reboot again.

Now it's time to check our bootchart.

Woot! 0:45. Great.

OK. I cheated. I also fixed some other stuff i noticed in my bootchart. But the main factor was the profilining.