Set Linux starts in multi-user mode as default.

ref:　　How to start Linux in multiuser mode rather than boot directly into XWindows (X11)

　　steps:

1. Log in to the server as root.
2. Type vi /etc/inittab.
3. When inittab opens, using the arrows keys move your cursor down till you see a line that looks like this 'id:5:initdefault:'
4. Press the i key to go into insert mode.
5. Type the number 3. The line should now appear as 'id:3:initdefault:'
6. Press the escape key to exit insert mode.
7. Type :wq and press enter to save and exit vi.