How to make Linux boot faster

Linux can bootup very slow or fairly fast depending on how its setup. Most Linux distributions load allot of unnecessary stuff, that can be easily disabled.

Boot loader
Make sure the timeout is set to a low number 2 seconds is fine.


 * Grub
 * Edit: /boot/grub/grub.conf
 * Modify line: timeout 2


 * lilo
 * Edit: /etc/lilo.conf
 * Modify line: timeout 2

Init processes

 * Disable unneeded processes
 * Commands
 * Gentoo
 * rc-update (console)
 * rc-config (console)
 * Fedora/RHEL:
 * /usr/bin/system-config-services
 * /usr/sbin/serviceconf
 * /usr/sbin/ntsysv (console)
 * chkconfig (console)
 * Red Hat:
 * /usr/bin/redhat-config-services
 * /usr/sbin/ntsysv (console)
 * Ubuntu / Debian:
 * bum (Boot Up Manager) (GUI)
 * /usr/bin/services-admin (GUI)
 * /usr/sbin/sysv-rc-conf (console)

this list contains services from many different distributions, your system wont have all of them. ''* The remove recommendations, simply mean they are not required for normal operation. But if you want that feature to work, you need to enable it. For example if you want to use a printer, you need to enable CUPS.''
 * List of init processes
 * Enable parallel loading
 * Gentoo Linux
 * Edit: /etc/conf.d/rc:
 * Set: RC_PARALLEL_STARTUP="yes"

kernel

 * Recompile Kernel to fit your system
 * Remove any unneeded components, you may be able to find the exact components required for your computer, and remove hundreds of unnecessary and unused ones.


 * Use gzip compression on Kernel
 * gzip decompresses faster than Bzip2 and LZMA.


 * General setup --->
 * Kernel compression mode (Gzip) --->

Make sure system is properly configured
Things can load slower if you system has to test and guess settings. X windows loads slower if your host is not set.


 * Make sure configs match
 * Hostname (gentoo)
 * for example hostname=tux networkname=tuxnet
 * Edit: /etc/hosts
 * Modify: 127.0.0.1	tux tux.tuxnet localhost
 * Edit: /etc/conf.d/net
 * Modify: dns_domain_lo="tuxnet"
 * Edit: /etc/conf.d/hostname
 * Modify: HOSTNAME="tux"

Other advice

 * See How To Make Ubuntu Faster for Ubuntu Distributions of Linux
 * See http://linux.aldeby.org/speed-up-your-ubuntu-linux-boot.html for some other good tips
 * See How to tweak and optimize SSD for Ubuntu, Linux Mint for tweaking SSD/HDD on Linux.