Comment Prevent Physical Access (Score 1) 539
There are two ways that I can think of to prevent this.
1) Take a bike lock and wrap it around your server, chaining it closed and to everything nearby. They won't be able to root it easily, because the drive is locked in.
2) Go to the datacenter and pick up your server. Hide it in another companies racks, somewhere inconspicuous, and hope they don't follow any wires.