Right, so this means that the IT department in the summary could buy a new storage system every month, since they are charging $30/GB per month.
Actually, no it doesn't.
They have already paid over $25 dollars for every GB that they offer to the rest of the company.
Now, if you want to reduce these costs, you have to do a risk assessment. Under the model described in AUD above, there are at least 5 copies of a given set of data. Do you NEED the two DR copies ? Depending on the processing model, some intermediate files don't need to have any more than a single copy. In other words, storage space CAN cost $25 - $30 / GB, but thats for the rolls royce version.
Just make sure that if you ask for the Trabant version, that's really all you need.