Disable GUIs and X Windows on Linux VMs

by Bob Plankers on December 2, 2011 · 7 comments

in System Administration,Virtualization

This is post #2 in my December-long series on Linux VM performance tuning, Tuningmas.

I remember an old story about people having performance issues on their Windows servers. It would happen intermittently, and never when the system administrator was around. Turns out it was the pretty OpenGL screensaver, which would kick in and slow everything down tremendously. When the admin was around he’d be using the console of the server, so no screen saver, and no problems.

Graphical user interfaces make one-off administration tasks easier in some cases, but for virtual environments they come at a cost: additional RAM and CPU overhead. For a virtual environment you should shut them off, or install as little of them as you need, and only run them when you need them.

To disable the GUI from automatically starting at boot change this line in /etc/inittab from:

id:5:initdefault

to

id:3:initdefault

That way, on boot you’ll enter runlevel 3, which is full multiuser operations but no GUI (runlevel 5 is full multiuser with GUI). You can then start the GUI from the command line with the command ‘startx’ and exit by pressing Ctrl-Alt-Backspace.

Not so bad, eh? But don’t leave it running, and don’t use a fancy screensaver. :)

 

I started calling this series “Tuningmas” as a play on the fact I’m doing it in December and the Christian religious holiday that is nearby, temporally. Did you know that the word “Christmas” is a compound word that means “Christ’s Mass?” Until recently I hadn’t thought about it. Unlike most religious masses I encourage you to comment, especially if you see I’ve missed something, have made a mistake, or there’s something new since I posted this. There’s nothing holy about this blog, for sure. :)

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