One of the issues that datacenter efficiency metrics have as yet been unable to easily quantify is what the spending in the datacenter is actually paying for; that is, how we relate the total cost of datacenter spending to the work being done by the datacenter. To that end, eBay has developed its Digital Service Efficiency metric which gives them a dashboard view relating the full cost of datacenter operation to the buying and selling transactions that define their business.
The dashboard combines metrics from the Green Grid (PUE, CUE, WUE) along with information on actual power use, users, transactions, physical servers, and other key factors to deliver efficiency information in four areas of interest to executive management: revenue, performance, environment, and cost.
The graphic actually reveals information on the number of servers in use, something that few large Internet-based businesses have been willing to share.
The actual DSE dashboard is specific to eBay, but they believe that the methodology can be applied to many business models. In loose terms, the process is as follows:
- Determine the top-level services offered to customers
- Examine how users utilize the services provided
- Quantify the energy consumed for each top level service
- Both direct and indirect consumption in kilowatt hours
- Establish appropriate currencies
- Follow the flow of software through the business workflow and determine appropriate currencies for each layer
- Discover the knobs
- Look to see what variables can be tuned to improve the various business processes and look at how to balance service delivery with efficiency
Referring to it as a “Mile Per gallon” approach, eBay is using their DSE measurements to establish 2012 as a baseline and to set efficiency goals for 2013. They look to increase the transactions by kWhr by at least 10% while reducing costs and carbon footprint by at least 10% as well.