Page 57 - How Cloud Computing Is Transforming Business and Why You Cant Afford to Be Left Behind

THE AMORPHOUS CL OUD

If more resources are needed, the chances that the cloud
can summon them are high. It would be expensive for cloud
providers to keep massive amounts of surplus facilities sitting
around unused day after day waiting for a rare spike. But the
cloud doesn’t have to do that because it is a multitenant facil-
ity, with many customers using the same servers, and in some

cases the same software. The cloud managers make an edu-
cated guess at how much surplus capacity is safe to maintain;
their advanced load-balancing systems can anticipate need,
adding more servers for more direct power, while at the same
time moving workloads around to underutilized servers.
The cloud’s operations managers base their estimate of
what constitutes a safe surplus on the analysis of server logs and

historical patterns from monitoring the servers’ total work-
load. Managers also hope that not every cloud customer will
create a major spike at the same time, an admittedly rare pos-
sibility. This appearance of expandable capacity for any single
end user is to some extent an illusion. Somewhere, as with all
material things, there is a limit to how many major spikes
could be met at one time in any given cloud data center. But
with thousands or tens of thousands of customers, what is the
likelihood that the cloud provider will experience a surge in

need from a majority of its customers at the same time?
In the normal course of operations, multiple customer
spikes are infrequent and, fortunately, spikes rarely travel in
herds if the customers are varied in their business makeup. A
cloud’s monitoring system can show warning flags, send alerts,
or sound alarms; somewhere behind the automated system is

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