We have been hearing a lot about cloud computing these days and this technology has gained a lot of momentum now. But cloud security still remains a concern for everyone. Which is a better option: private or public cloud? Let’s take a look.
 

Public Cloud : A public cloud is nothing but outsourcing your data centre. An external company offers up its data centre for rent and one can choose the number of servers or the amount of storage that needs to be run there, as well as applications. It can then be accessed remotely from a PC. The USP of this model is cost saving. You save your hardware cost as well as its maintenance and staffing cost.
There is also a widely adopted “pay as you go” model with public clouds, allowing you to rent the space from as little as an hour – often used by developers testing applications – up to months or years. The public cloud space is dominated by players like Amazon and Google although smaller companies like Elastic Hosts are getting in on the act too whilst firms like Salesforce.com offer the ability to run a single application in the cloud.
Private Cloud : A private cloud is a more personal environment. This model keeps all of your physical hardware within your own location, meaning the day to day running of the systems, maintenance, and – most importantly – security aspects, are run in house.
This is more helpful to larger institutions like banks or the public sector, who are concerned about their security of their data. EMC is a large advocate of this but many of the other hardware vendors such as HP, IBM and Dell offer software solutions and specifically designed products to cope with the new environment

Pros and Cons
Both the above are acceptable and workable models but they come with their own positives and negatives. Businesses that use public cloud can enjoy the benefits that come with any large scale deployment such as highly available, enterprise class infrastructure, but at a fraction of the cost. Also when you sign up to fit out your data centre with all the products you need, companies can end up locked in and stuck with those products for a very long time.
The pay as you go model adopted within the public cloud means if you aren’t happy with the service you are receiving there is no such thing as vendor lock- in and you can jump ship at any time – but only if such clouds work on the same standards and are interoperable.
However, the flip side of this coin is businesses are concerned about the security of their data. For some companies the idea of letting anything out from their boundary is a terrifying prospect. In a large scale data centre owned by a public cloud company, you would not know whereabouts of your data and who else had their data running on the same machines.
The companies insist that there is strong security measures put in place but this means you would need to have a lot of trust in whichever firm you went with. On top of that we know the providers look at the data – Google has admitted publicly it looks at data for marketing purposes.
Also, despite the claims of high availability, public cloud vendor’s data centers are just like any other and can go down. It may not be often and also may be fixed quickly but your business could be left without accessibility to the core functions it needs to run.
So the alternative to this is private cloud. Businesses have the ability to fully customise their cloud environment. There is a lot of control when building a private cloud within your own data centre. The hardware chosen, the software chosen, the people taking care of the heartbeat of many an organisation are handpicked, all by you and your business.
A fully functioning virtualised data centre can really take advantage of those boxes and get the best out of them. Less physical machines still means many virtual ones and as well as lowering the total cost of ownership, the simple yet expensive elements of power and cooling take a cut too.
But yet again here comes the cost factor. Though it is cheaper and more productive than the traditional data centre but the cost is still higher as compared to the public cloud.
A business will be forced to purchase the entire infrastructure themselves to put a private cloud in place, forcing them into vendor lock-ins they may have preferred to escape. They will also have to invest considerably in maintaining their infrastructure.
So which is best ?
According to EMC, all clouds should be private as the organizations are totally in control of their environment. Yet equally large companies like Amazon Web Services are more vocal about the public cloud, and incredibly dismissive of the private model. However, there are companies who feel the future of cloud is hybrid cloud (a mixture of both). A move to hybrid cloud gives companies, particularly the larger ones, the best of both worlds.
Despite the pros and cons of both the models, and even with hybrid cloud, it all depends on the individual needs and the budget of the organization. A small business that doesn’t want to own a data center and IT staffs to run, can perhaps head for the public cloud. But an established business that has just invested in tons of infrastructure, can go for the private cloud.
One should opt for whatever is right for their business.