I often hear the opinion presented as fact: “shift everything to the Cloud because that is the most efficient space”. The arguments usually consist of the following reasons:
- The bigger the data centre the more efficient it can be in utilising cooling and power infrastructure
- The bigger the data centre the better bargaining power with the electricity companies, because they love data centre loads which are nice and stable
- Average utilisation rates for individual servers are so low (about 10-15% – even with virtualisation), that Cloud could help to boost that by sharing loads with multiple clients
The problem with all these arguments is that they assume that everyone is at the same starting point. We are currently undertaking a project (see previous post) to measure and report on individual service costs. This project should enlighten us as to whether we are right to host our own services or whether we would be better off hosting them elsewhere, in the cloud. What we won’t be doing is making any assumptions about the business case for the cloud and, in my opinion, neither should you.
Other arguments against cloud efficiency are numerous, but here is my main one:
“Cloud” data centres, however you define them, are not necessarily as efficient as a corporate data centre. In fact, one could argue that they are much less efficient than a corporate data centre and that Facebook, Google and Microsoft, etc are examples of “Corporate” data centres and not “Cloud” data centres, since their data centres exist to promote their business models (e.g. search, email and document sharing).
In my opinion, the true cloud offerings these companies also promote should be taken separately. Cloud computing data centres must have, by definition, capacity to grow and shrink as demand requires – this means that their utilisation will vary and their efficiency (not measurable by PUE alone) will also vary but will necessarily be poor more often than not – unless they consistently over-subscribe their capacity and prioritise certain customers over others…
Consider the analogy that is often used to describe cloud computing – an “electricity grid”. When one plugs into a socket, more often than not electricity is supplied to power whichever device is connected. Within limits we can power all the devices in our home from the one supply. This is great for us but a nightmare for power station operators, who manage this daily headache consistently round the clock. Skilled operators watch TV in order to guess when the kettle may be switched on and so try and pre-empt a massive surge in demand as households around the country reach for the coffee tin or teacup. Do you know of any cloud providers that do this yet?
No doubt, when DCIM becomes intelligent enough and fully integrated into the data centre, with robust, mature processes to make best use of it, then the efficient management of infrastructure along with demand may become a reality. Until then, cloud is not the “green” panacea that everyone thinks it is – far from it.
I believe that CTOs and CFOs need to demand better use of power in their corporate data centres. Many data centre managers are waking up to this fact and in Europe, while still in its infancy, the EU Code of Conduct for Data Centres is a welcome step in the right direction to assist and encourage this activity.