VM (QEMU) screen resolution change
The default resolution in most XenCenter VMs are crap. Trying to work with 800x600 resolution is like looking through a submarine porthole. Let's increase the resolution of the VM:
sudo apt-get install xvfb xfonts-100dpi xfonts-75dpi xfstt
sudo nano /etc/default/grub
Press CTRL+W to search for the string below:
Set the line to the following. You can change the resolutions below to suit your preferred order. The first entry will be used on default. Don't forget you can set it pretty high and then just click the "scale" option in the console window of XenCenter.
The add this underneath that line:
Save the config file with CTRL+X and select "Y" to confirm changes.
Now reboot once the updates are all finished installing.