A Complete Explanation of Cloud Computing
By Robb Kimmer
For the last couple of years the IT industry has been getting excited and energised about
Cloud. Large IT companies and consultancies have spent, and are spending, billions of dollars,
pounds and yen investing in Cloud technologies. So, what's the deal?
While Cloud is generating lot more heat than light it is, nonetheless, giving us all
something to think about and something to sell our customers. In some respects Cloud isn't
new, in other respects it's ground-breaking and will make an undeniable change in the way that
business provides users with applications and services.
Beyond that, and it is already happening, users will at last be able to provide their
own Processing, Memory, Storage and Network (PMSN) resources at one level, and at other levels
receive applications and services anywhere, anytime, using (almost) any mobile technology.
In short, Cloud can liberate users, make remote working more feasible, ease IT management and
move a business from CapEx to more of an OpEx situation. If a business is receiving applications
and services from Cloud, depending on the type of Cloud, it may not need a data centre or server-room
any more. All it will require is to cover the costs of the applications and services that it
uses. Some in IT may perceive this as a threat, others as a liberation.
So, what is Cloud?
To understand Cloud you need to understand the base technologies, principles and drivers
that support it and have provided a lot of the impetus to develop it.
For the last decade the industry has been super-busy consolidating data centres and server-rooms
from racks of tin boxes to less racks of fewer tin boxes. At the same time the number of applications
able to exist in this new and smaller footprint has been increasing.
Virtualisation; why do it?
Servers hosting a single application have utilisation levels of around 15%. That means
that the server is ticking over and highly under-utilised. The cost of data centres full of
servers running at 15% is a financial nightmare. Server utilisation of 15% can't return anything
on the initial investment for many years, if ever. Servers have a lifecycle of about 3 years
and a depreciation of about 50% out of the box. After three years, the servers are worth anything
in corporate terms.
Today we have refined tool sets that enable us to virtualise pretty much any server and
in doing that we can create clusters of virtualised servers that are able to host multiple
applications and services. This has brought many benefits. Higher densities of Application
servers hosted on fewer Resource servers enables the data centre to deliver more applications and services.
It's Cooler, It's Greener
Besides the reduction of individual hardware systems through expeditious use of virtualisation,
data centre designers and hardware manufacturers have introduced other methods and technologies
to reduce the amount of power required to cool the systems and the data centre halls.
These days servers and other hardware systems have directional air-flow. A server may have
front-to-back or back-to-front directional fans that drive the heated air into a particular
direction that suits the air-flow design of the data centre.
Air-flow is the new science in the IT industry. It is becoming common to have a hot-isle and
a cold-isle matrix across the data centre hall. Having systems that can respond and participate
in that design can produce considerable savings in power requirements. The choice of where to
build a data centre is also becoming more important.
There is also the Green agenda. Companies want to be seen to be engaging with this new
and popular movement. The amount of power needed to run large data centres is in the Megawatt
region and hardly Green. Large data centres will always require high levels of power.
Hardware manufacturers are attempting to bring down the power requirements of their products
and data centre designers are making a big effort to make more use of (natural) air-flow. Taken
together these efforts are making a difference. If being Green is going to save money, then it's a good thing.