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linuxvirtual-machinevirtualboxmonitorheadless

Disabling monitor on an headless virtual machine

I set up a virtual machine with Ubuntu Server edition. When I boot it up, the output from the console appears on VirtualBox's virtual screen. This means the machine is wasting resources trying to display output on a screen. It's just a text terminal, I know, but it still requires resources. Why waste them when I'm going to only access remotely through PuTTY?

I know that VirtualBox can start a virtual machine in "headless" mode, but I fear it will just disable VirtualBox's output window, with no real impact on the virtual machine itself.

My questions are:

  • Will my virtual machine still detect a monitor attached when it runs in headless mode?
  • If so, how big is the performance impact of this situation? Is there any way to avoid it?
Solution

  • It does not require any additional resources. Just a tty device and a blocking getty process which requires no CPU resources and which has would both have been created anyway. (Every Linux system that I know starts 6 ttys by default).