Your server is protected with our "Continuous Data Protection" 4 times per day backups system to a remote location at another datacentre. You can read more here, and it is included in your dedicated server plan:
Continuous Data Protection (CDP)
Should you still wish to have a second drive in any of our server offerings, we can accomodate but it isnt really something we recommend due to the investment we have made in the above system for added piece of mind.