Johnathen Koomey writes 4 main advantages of going in the cloud:
- Economies of scale. It’s cheaper for bigger cloud computing folks to make efficiency improvements because they can spread the costs over a larger server base and can afford to have more dedicated folks focused on efficiency improvements.
- Diversity and aggregation. More users, more diverse users, and more users in different places means computing loads are spread over the day, allowing for increased equipment utilization. Typical in house data centers have server utilizations of 5-15 percent and sometimes much less, whereas cloud facilities for major vendors are more in the 30-40 percent range.
- Flexibility. Cloud installations use virtualization and other techniques to separate the software from the characteristics of physical servers (some call this “abstraction of physical from virtual layers”). This sounds like a great thing for software and total costs, but why is it an energy issue?
- Using this technique means that you can redesign servers to optimize them and drop certain energy costly features. For example, if software can route around physical servers that die, you no longer need to have two power supplies in each server; the death of any one particular server doesn’t matter to the delivery of IT services.
- Ability to sidestep organizational issues instead of having to address them head-on (which is hard and slow). While most company in-house IT operations face the problem of a disconnect between IT departments driving server purchases, and facilities departments paying the electric bill, that problem has largely been solved for the cloud providers. They generally have one data center budget and clear responsibilities assigned to one person with decision making authority.