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Private Vs Public Cloud
Article · August 2013
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ISSN:2249-5789
Solanke Vikas et al, International Journal of Computer Science & Communication Networks,Vol 3(2), 79-83
Private Vs Public Cloud
Solanke Vikas 1, Kulkarni Gurudatt 2, Maske Vishnu 3 , Kumbharkar Prashant 4
1 Lecturer in Information Technology Department,MM Polytechnic Pune, India
solankevs@mmpolytechnic.com
2 Lecturer in Electronic and Telecommunication Department,MM Polytechnic Pune, India,
kulkarniga@mmpolytechnic.com
3 Lecturer in Computer Department, Government Polytechnic, Mumbai, India.
vdmaske@yahoo.com
4 Head of Computer Department,Siddhant College Of Engineering, Pune, India.
Abstract
The main objective of the Private Cloud Hosting industry came out of the need for software and
platforms is to optimize IT resources involved in the computing services that were managed internally, but
cycle of corporate provisioning, delivery, monitoring were made more economical and accessible through the
and control of business-critical applications: the economies of scale of a hosted implementation.Cloud
elasticity of supply storage, processing and networking, computing as a computing model, not a technology. In
on-demand access to systems, self-provisioning by the this model “customers” plug into the “cloud” to access
user or workgroup, through a centralized management IT resources which are priced and provided “on-
dashboard unified system administrators, workgroup demand”. Essentially, IT resources are rented and
managers and end users. The decision to pursue cloud shared among multiple tenants much as office space,
computing is one that many organization have or will apartments, or storage spaces are used by tenants.
make as this technology grows and matures. But this Delivered over an Internet connection, the “cloud”
decision need not be one fraught with uncertainty. With replaces the company data center or server providing
a little due diligence, and answering a few key the same service. Thus, Cloud Computing is simply IT
questions, you can ensure that your cloud vendor services sold and delivered over the Internet[9,8].
selection is a sound one. Nature of public cloud
architecture depends upon sharing and accessing data 2.0 CLASSIFICATION OF CLOUDS:-
within inhouse It premises as well as third parties. Cloud Computing can be classified into 4 types on the
Although, this type of cloud form does raises an alarm basis of location where the cloud is hosted:
in terms of security, but is equally efficient like private
cloud architecture. Factors like scaled up environment Public Cloud: Computing infrastructure is
and bandwidth uptime is also catered in this type of hosted at the vendor’s premises. The customer
cloud form. has no visibility over the location of the cloud
computing infrastructure. The computing
Keyword: - Public, Hybrid, Offline, Platform. infrastructure is shared between organizations.
Private Cloud: Computing architecture is
. dedicated to the customer and is not shared
1.0 What is Cloud Computing? with other organizations. They are expensive
and are considered more secure than Public
Cloud computing broadly describes off-premise, Clouds. Private clouds may be externally
ondemand computing where the end-user is provided hosted ones as well as in premise hosted
applications, computing resources, and services clouds.
(including operating systems and infrastructure) by Hybrid Cloud: Organizations host some
clouds services provider via the Internet. The hosting critical, secure applications in private clouds.
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ISSN:2249-5789
Solanke Vikas et al, International Journal of Computer Science & Communication Networks,Vol 3(2), 79-83
The not so critical applications are hosted in
the public cloud. The combination is known as
Hybrid Cloud. Cloud bursting is the term used
to define a system where the organization uses
its own infrastructure for normal usage, but
cloud is used for peak loads.
Community Cloud: The cloud infrastructure is
shared between the organizations of the same
community. For example, all the government
agencies in a city can share the same cloud but
not the non government agencies.
Any enterprises are beginning their cloud evaluation
with a "private cloud." I extend the definition of private
cloud to be a "single tenant" cloud, as some enterprises
may chose to use a single tenant cloud hosted at a
service provider, versus hosting their cloud within their
own data centers. In the following diagram, we show
two private clouds, connected via policy-based
replication in two data centers. This provides the
assurance of backup and disaster recovery that many
enterprises require. A third location could easily be
added for even higher levels of backup and disaster
recovery.
3.0 Public Cloud Vs Private Cloud
Public cloud is used as a service via Internet by
the users, whereas a private cloud, as the name
conveys is deployed within certain boundaries like
firewall settings and is completely managed and
monitored by the users working on it in an
organization.
Users have to pay a monthly bill for public cloud
services, but in private cloud money is charged
on the basis of per GB usage along with
bandwidth transfer fees.
Public cloud functions on the prime principle of
storage demand scalability, which means it requires no
hardware device. On the contrary, no hardware is
required even in private cloud, but the data stored in the
private cloud can only be shared amongst users of an
organization and third party sharing depends upon trust
they build with them. It is also entirely monitored by
the business entity where it is running. The growth of storage is driving increased costs, and
The following diagram reviews the differences the enterprise is on a continuous search to improve the
between public and private clouds: way they can cost-effectively manage this growing
data. The primary difference between hybrid cloud and
private cloud is the extension of service provider-
oriented low cost cloud storage to the enterprise. The
service provider based cloud may be a private cloud
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ISSN:2249-5789
Solanke Vikas et al, International Journal of Computer Science & Communication Networks,Vol 3(2), 79-83
(single tenant) or a public cloud (multi-tenant). There environment that is shared with a number of other
are several implementations of hybrid cloud, and clients or tenants.
several examples are included. The service provider
cloud may enable enterprises to leverage the volume
efficiencies of the service providers to realize
additional savings. The private cloud, or enterprise
cloud, is where the infrastructure is created or set up
solely for one organization. Management of the
infrastructure can be done in the comfort of the site of
the organization itself. But if the company chooses, it
can also be managed offsite, either as a hosted or
managed cloud, by a service provider. Public cloud, on
the other hand, is the type of infrastructure that serves a
number of tenants. Most of the tenants are small scale
businesses and the general public. The ownership of the
resources is in the hands of the business that sells the
service. When it comes to privacy and security, it is the
private cloud that works best. One can be sure that all 3.1 PUBLIC CLOUDS AMAZON EC2 AND
data and information are secure. This is especially great ACKSPACE CLOUD TRADEOFFS [1,
for companies that do specialized research and 2]
development or those that work for the government. Utility Model – Public Clouds typically deliver a
Furthermore, additional security measures may be pay-as-you-go model, where you pay by the
installed. Also companies with huge databases can hour for the computer resources you use. This is
greatly benefit from using the private cloud. On the an economical way to go if you’re spinning up &
issue of scalability, the public cloud is more efficient. tearing down development servers on a regular
Unlike the private cloud whose scalability potential is basis.
restricted or limited due to the company’s limited No Contracts – Along with the utility model,
emises, the public cloud shares more common you’re only paying by the hour – if you want to
resources which make it more scalable. The client shut down your server after only 2 hours of use,
business does not have to worry about additional there is no contract requiring your ongoing use
servers as this is the job of the provider. Virtualization of the server.
knowledge is another issue to consider. Though there Shared Hardware – Because the public cloud is
have been attempts at creating a company’s own by definition a multi-tenant environment, your
private cloud, the problem comes in when there is the server shares the same hardware, storage and
lack of expertise and experience of the employees. The network devices as the other tenants in the cloud.
staff that handles this area should be knowledgeable. Meeting compliance requirements, such as PCI
This is not a problem for the public cloud. Another or SOX, is not possible in the public cloud. No
important consideration is pricing. The private cloud is, Control of Hardware Performance – In the
obviously, more costly that the other one. If the public cloud, you can’t select the hardware,
company does not need the advanced security features cache or storage performance (SATA or SAS).
and network latency, then the public cloud will do as it Your virtual server is placed on whatever
is more affordable. And for now, what is most hardware and network, the public cloud provider
necessary to do for companies is to start transferring designates for you.
their files to the cloud and be able to compete with the Self Managed – with the high volume, utility
rest of the business world. The majority of public cloud model, self managed systems are required for
deployments are generally used for web servers or this business model to make sense. Advantage
development systems where security and compliance here for the technical buyers that like to setup
requirements of larger organizations and their and manage the details of their servers.
customers is not an issue. Private cloud computing, on Disadvantage for those that want a fully
the other hand, by definition is a single-tenant managed solution.
environment where the hardware, storage and network The majority of public cloud deployments are
are dedicated to a single client or company. The public generally used for web servers or development
cloud is defined as a multi-tenant environment, where systems where security and compliance
you buy a “server slice” in a cloud computing
requirements of larger organizations and their
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ISSN:2249-5789
Solanke Vikas et al, International Journal of Computer Science & Communication Networks,Vol 3(2), 79-83
customers is not an issue. Private cloud hosting, expertise to build the infrastructure and
on the other hand, by definition is a single-tenant automation required to stand up and operate a
environment where the hardware, storage and private cloud. Case studies show that it
network are dedicated to a single client or involves much up-front investment in time and
company. resources compared to simply going with a
public cloud. However, there are many up and
3.2 PRIVATE CLOUD COMPUTING coming startups that are offering private cloud
TRADES-OFFS: [2] related services and products that
Security – Because private clouds are organizations can use in their internal data
dedicated to a single organization, the center. While these products still need time to
hardware, data storage and network can be mature and become mainstream, this
designed to assure high levels of security that represents a significant shift towards the
cannot be accessed by other clients in the availability of the technology required to
same data center. install and manage private cloud computing
infrastructures. These product and service
Compliance – Sarbanes Oxley, PCI and
HIPAA compliance cannot be delivered offerings could mitigate some of the risks and
through a public cloud deployment. Because challenges and blur the line between a private
the hardware, storage and network and public cloud.
configuration is dedicated to a single client, 3. Size of the organization: Not all organizations
can afford to build a private cloud for the two
compliance is much easier to achieve.
reasons listed above. Crafting a business case
Customizable – Hardware performance,
for building a private cloud for a smaller
network performance and storage performance
organization is difficult, since building the in
can be specified and customized in the private
house infrastructure for the private cloud does
cloud.
not provide as much of a return on investment
Hybrid Deployments – If a dedicated server is as larger cloud deployments do. The public
required to run a high speed database
cloud provides impressive benefits related to
application, that hardware can be integrated economies of scale, and smaller organizations
into a private cloud, in effect, hybridizing the will find it difficult to build a private cloud
solution between virtual servers and dedicated solution that can match that.
servers. This can’t be achieved in a public
cloud.
3.2 CHALLENGES OF A PRIVATE CONCLUSION
CLOUD [1] A private cloud, because it functions independently
There are a few constraints and challenges that would for an organization and that too behind firewall settings
make the public cloud model more appealing to a lot of does prove to be accessible. By stating this, we mean
organizations. There are inherent challenges with that a private cloud cannot be accessed from anywhere
private cloud that need to be addressed before an and at any point of time. It is completely managed by
organization can venture down the path of building the users working for an organization. Public cloud
one. architecture is built with the view to create an
1. Upfront Capital Cost: One of the drawbacks of accessible business environment that can be shared and
private clouds is that organizations still need accessed from anywhere and at any time of the hour.
to buy, build and manage the cloud Even though, it poses security risks, public cloud is
infrastructure, which defeats the primary considered more useful than its counterpart because of
premise of cloud computing. One of the key several reasons, Initial cost is minimal, but if data is
value propositions of cloud computing is that stored for a long period of time, it proves to be
it drastically reduces the upfront capital cost of expensive. However, the cloud acts as an excellent
in-house infrastructure, while providing the source for different types of data than a particular type
same or better service for a simple recurring of it. More accessible than the private cloud as it can be
operational cost. This benefit cannot be accessed from anywhere round the globe. Availability
realized with private cloud infrastructures. and reliability are the two factors that make public
2. Time and Resources: Not all organizations cloud computing service more popular. The reason
have the time or resources with in-house being, it is available to users via web installed at a
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ISSN:2249-5789
Solanke Vikas et al, International Journal of Computer Science & Communication Networks,Vol 3(2), 79-83
given server off-premises. Public cloud’s advantage
includes low upfront cost, with practically infinite
scalability, it has a significant downside especially in
accountability, security, and lock-in.
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