Information Technology Reference
In-Depth Information
benefits of the cloud. Still a quantitative analysis
of the relevant aspects of the potential IT problem
is required before making a decision on the ap-
propriate development and infrastructure model.
IT managers are recently faced with the
problem of making a selection between cloud
computing and on-premise development and
deployment. Cloud computing option is attrac-
tive, especially if the quality delivered and the
total cost is satisfying and the risks are reason-
able. The real question for many IT departments
is whether the cost of transition to an external
computing cloud will be low enough to benefit
from any medium-term savings (Armbrust et al.,
2008), (Cloud Computing Congress, 2010). In
order to be able to provide answers to the above
question, a formal cost analysis of cloud and
on-premise deployment should be performed in
order to compare thoroughly the two alternatives.
A thorough analysis of the estimated costs and
quality associated with the two alternatives will
help an IT manager define the pros and cons of each
solution. Such an analysis will point out which is
the right combination of cloud and premise based
assets and can indeed provide the optimal solu-
tion. As mentioned by Knight, (2009) the key is
not choosing between the two solutions but being
strategic about where to deploy various hardware
and software components of a total solution.
Although there is a lot of research dedicated
to cloud computing software engineering issues,
economics and cost estimation drivers for adopt-
ing such a technology are not systematically ad-
dressed. This chapter presents basic parameters
for estimating the potential benefits from Cloud
computing and provides an estimation framework
for determining if it is a technology that offers
a long term profitable solution to IT business
problems. Basic parameters for estimating the
potential costs deriving from building and deploy-
ing applications on cloud and on premise assets
are presented.
The assessment of cloud computing costs is
more evident compared to the assessment of on
premises development and deployment. The cost
of cloud computing services initially depends
on the usage of three types of delivery models;
namely, software-as-a-service, platform-as-a-
service and infrastructure-as-a-service. The usage
is counted and billed based on the committed
resources per hour or the number of users per
hour. As the cloud technology is relatively recent,
measurement standards are not yet fully defined
for each model. The usage metrics should be care-
fully selected in order to provision and receive
effective services (Dikaiakos et al., 2009). The
metrics that nowadays are frequently used are
bandwidth, CPU, memory and applications usage,
per hour. The target of this chapter is to discuss
and suggest appropriate metrics that is/will be
used for billing cloud computing services. These
metrics will also be used to estimate the cost of
an application moving or being developed over
the cloud. Other important parameters that should
be taken into account in order to evaluate cloud
computing adoption is the business domain and
objectives of the application considered, demand
behaviour in the particular field and technical
requirements (Klems et al., 2009). Of course this
estimation would help in order to approximately
predict the cost of cloud computing adoption, but
still one should be able to estimate the costs of
the alternative privately owned solution in order
to compare them and make a justifiable choice.
Estimating the cost of software development
and deployment based on on-premise assets is a
more complex procedure. On-premises applica-
tion development includes a variety of different
costs associated with IT infrastructure and soft-
ware development. Estimating in-house develop-
ment and deployment of software is a difficult
task, as there are different cost drivers related
to personnel, product, process, hardware and
operation expenses. Developing applications on
privately owned IT infrastructure comprise, apart
from software development and maintenance costs
which remain the same in both cases, a series of
cost drivers associated with physical attributes,
Search WWH ::
Custom Search