Wednesday, January 19, 2011

Types of Clouds in Cloud Computing

Types of Cloud Computing

In my earlier article on Cloud Computing I discussed about the cloud, its overview advantages and current situation. In this post I am going to discuss about the type of clouds and what is the difference between them. This would provide a clear understanding of various kinds of clouds and scenarios where they are useful.

1. Public Cloud
2. Private Cloud
3. Hybrid Cloud

I will discuss them along with their adavantages and short-comings:

Public Clouds

These are the clouds which are open for use by general public and they exist beyond the firewall of an organization, fully hosted and managed by service provider and they make resources, such as applications and storage, available to the general public over the Internet. Some of the service providers are Google, Amazon, Microsoft. They strictly follow “Pay as you go” model which helps start ups to start small and go big without investing much in the IT infrastructure. Here a user does not have a control on the management of the resources. Everything is managed by the third party and it’s their responsibility to apply software updates,security patches etc . This means that IT systems are shared by various users to a very high degree, and since the networks are not separated, the user doesn‘t really know where his data is stored. A Public Cloud offers the best potential in terms of cost-effectiveness, but it only offers nominal data protection and specific availability. Public clouds typically charge a monthly usage fee per GB combined with bandwidth transfer charges. Users can scale the storage on-demand and will never need to purchase storage hardware. Service providers manage the infrastructure and pool resources into capacity that any customer can claim.

The main benefits of using a public cloud are:
  • Easy and inexpensive set-up because hardware, application and bandwidth costs are covered by the provider.
  • Scalability to meet needs.
  • No wasted resources because you pay for what you use.

Some issues related to public clouds are:
  • The user of public clouds have no control where their data is saved.
  • Security and data protection is of nominal type.

Private Clouds

Private cloud (also called internal cloud or corporate cloud) is a marketing term for a proprietary computing architecture that provides hosted services to a limited number of people behind a firewall. Advances in virtualization and distributed computing have allowed corporate network and data-center administrators to effectively become service providers that meet the needs of their "customers" within the corporation. Private Clouds emulate cloud computing on private networks. These (typically virtualization automation) products offer the ability to host applications or virtual machines in a company's own set of hosts. These provide the benefits of utility computing -shared hardware costs, the ability to recover from failure, and the ability to scale up or down epending upon demand. Private Clouds represents an enterprise-specific environment with dedicated IT systems as well as private access and sharing. The strictest rules can be defined and implemented individually. When Private Clouds are established and hosted on the premises of the organazation consuming it, they are also referred as to On-Premise Private Clouds. Private clouds are built from software running on customer-supplied commodity hardware. The storage is typically not shared outside the enterprise and full control is retained by the organization. Scaling the cloud is as simple as adding another server to the pool and the self-managing architecture expands the cloud by adding performance and capacity.

The main benefits of using private cloud are:
  • Enhanced security and data protection and one can raise it as much level as one wishes.
  • The user has total control of where the data is being saved.
  • Easily recover from failure.
  • Easy monitoring of demand for service and accordingly manage the cloud by scaling up or down.
  • Very useful for Enterprise IT organizations use their own private cloud(s) for mission critical and other operational systems to protect critical infrastructures.

Some issues related to private clouds are:
  • Do not benefit from lower up-front capital costs and less hands-on management, essentially lacking the economic model that makes cloud computing such an intriguing concept. Hence the cost of operation is high compared to Public Clouds.
  • Many critics argue in Private Cloud one only implement virtualization and that simply applying it in a datacenter doesn't make for cloud computing.
  • Virtualization does indeed allow for some variability in capacity but it is limited. And, the cost to expand that variability means additional capital expense for the company. That seems to run counter to some of the inherent benefits of cloud computing.

Hybrid Clouds

A Hybrid Cloud is a mix of both Public and Private Clouds consisting of multiple internal and/or external providers. Thus they utilize the benefits and core features of both the public and private clouds and leaving out the various shortcoming of both. This helps in achieving all the related goals of the end user with minimum investment. Thus the data and application that needs to be in the public scope and the data security and protection is not an issue there the public clouds are used and that data and applications that is of high importance and value and security and protection is key factor then they are put in the private clouds. Thus by the use of Hybrid Clouds one can achieve the desired goal of targeting the related cloud consumer as per the categorization of the data and application involved vs the importance and security of it. They suit the cloud computing strategy of many organizations at large. The real potential of hybrid clouds will be realized when organizations are able to swap processing between internal and external resources and spread applications across those boundaries.

The main benefits of using Hybrid Cloud are:
  • Use the type of cloud that suits the requirement for particular data and application
  • Merges the benefits of the Public and Private Clouds
  • Cost effective as compared to Public and Private Clouds keeping in mind the security and protection that is avaliable in it.
  • Suits many organizations needs and goals to achieve their cloud computing strategy.

Some issues related to Hybrid Clouds are:
  • The management of Hybrid Clouds can be a little complex.
  • Currently the swapping of processing between the public and private clouds are not avaliable.
  • The introduction of some policies and updation in data has to be done separately in both the public and private clouds that make up the hybrid cloud which can be time and resource consuming.

Things to consider while choosing a cloud

Whenever choosing a cloud just remember the following five questions in respect to the Clouds and your needs:
  1. Who manages it
  2. Who owns it
  3. Where it’s located
  4. Who has access to it
  5. How it’s accessed
    Once you have gone through these questions in respect of your needs try figuring out that which type of cloud suits your needs best. The features in respect of the above questions of the types of clouds can be summarized in the following figure:

    I hope this article will through light into the various kinds of clouds in the market and which one will best suit you. To know more about Cloud Computing refer to my previous article. For an example of implementation of cloud computing by Google read in article on Google Cloud Print.


    1. This helped me a lot in understanding the cloud computing. Thanks Jai !

    2. Good and informative article.

    3. Good article with a great overview.Very well and simply explained.Each of these points is important for realistic information.I appreciate your work here.That is extremely a wonderful concept which you have floated towards the entire world. Yes, cloud computing services has now become one of the utmost needs for the users/enterprises as it enable the host with almost 100% uptime with lots of features on the tail. Like many of us, I am not that aware about this idea and because of that I am now pushing myself to read blogs and news about cloud computing as well as discussion with this topic to fully understand this matter.
      Thanks for sharing this.

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