Simple Storage Cost Model (Part 1)

In the previous missive I described a means of assigning value to business data. In this post I will continue the discussion and show how to determine the storage costs associated with providing business data.

The cost of providing business data

The means by which IT organizations determine and assign costs are as varied as the organizations themselves. Some organizations may not have implemented any chargeback methodology or may use only hard dollar accounting costs. However, in order to gauge the true cost of data, the operational costs should be included as well.

Accounting costs

Acquisition costs (CapEx): The capital or acquisition costs are the easiest to calculate as you begin with a simple bottom-line number. In order to determine the true costs, however, it is important to understand that the capital acquisition costs typically represent less than half of the actual cost of acquiring and operating equipment.

Operational costs (OpEx): There are many operational costs that can be associated with a cost model. For the purposes of an IT cost model, at least three operational costs should be considered:

• Support personnel costs
• Maintenance (warranty) costs for the equipment
• Environmental (power and cooling) costs

Some IT environments will also include depreciation and floorspace costs to the calculation, while others may need to include specific taxes, insurance fees, or other costs specific to the enterprise.

Creating a cost model

Once you determine the components that you will include in the cost model, it is simple enough to enter these values into a spreadsheet to calculate the costs. The spreadsheet should capture the agreed upon major aspects, which include the capital and operational costs, including personnel, maintenance, and power and cooling. A typical operational time frame may be picked, such as three years to five years (depending upon the accounting practices currently in place within the enterprise).

Provided below is a very simple cost model demonstrating the costs associated with a single 800 TB disk storage unit over a five-year term. (Note: The specific costs shown are completely arbitrary and are supplied only for illustrative purposes).

Storage Cost Model
Acquisition Costs
Purchase 1 800TB Disk Unit		$1,100,000
Less any discounts or credits		$0
Total Acquisition Costs			$1,100,000
Operational Costs	Per Year	Term 5 years
Support Personnel	$91,000	$455,000
Maintenance (EXCLUDING first year)	$77,285	$309,140
Environmental	$51,300	$256,500
Total Operational Costs			$1,020,640
Total Cost			$2,120,640
Cost per TB			$2,650.80
Cost/TB/Month			$44.18

Although this model is still quite simple, I favor it as the starting point for determining actual storage costs. In particular, I am an advocate of being able to provide a “Cost per TB per Month” figure that can be referenced as IT clients request additional storage for new projects and systems.

The sample spreadsheet that was used in this example is available from Recovery Specialties.