Tom Brand (UK) - External, Internal or Hybrid - What Cloud is Best for Who?

The IT industry continues to debate whether an external, internal or hybrid cloud model is superior, with many now arguing that internal (private) clouds don't even exist. However, there is not really a debate to be had; no single deployment model is in fact the best for all organisations.

This is not to suggest that cloud computing isn't a viable option, far from it. Before any decisions can be made, however, organisations must have a clear understanding of the business drivers for considering cloud computing, thus enabling a defined set of service requirements to be developed. Based on the output of these, the process of selecting or implementing a cloud service and the model in which it is deployed can then take place.

The choice of deployment model is heavily dependent on a number of factors which ultimately boil down to cost, risk and business value. For the foreseeable future, CIOs and CTOs will need to do more with less as budgets continue to feel the squeeze. External cloud services typically involve no capital investment and offer highly flexible pay-as-you-use computing. Yet, these benefits are often diluted by insufficient SLAs and security and compliance limitations.

Whilst many SMBs can take advantage of external cloud services for their entire range of application requirements, larger organisations have to approach external cloud offerings with a different strategy in order to comply with data regulations and ensure service availability. Based on the current limitations of many external cloud offerings available today, it is unlikely large enterprises will move the majority of their infrastructure to the public cloud. Instead, enterprises may run a form of private cloud or combination of private and public cloud solutions (hybrid) based on the nature of their service requirements and constraints.

To provide the key benefits of cloud computing, two components are fundamental - economies of scale and automation. Only large enterprises and service providers really have the scale, budgets, resources and vendor relations necessary; this is why private clouds with all the characteristics of Amazon or Google services have a potentially very limited market. For organisations, like banks and government bodies, whose data must not be kept on a shared infrastructure in unknown locations, building a private cloud is one solution particularly as they typically have infrastructures sizable enough to deliver the required economies of scale. That said even these types of organisations are likely to struggle to create internal cloud services with the required price points and commercial flexibility based on the huge levels of capex needed to develop and implement such solutions.

One compromise to the problem is the ‘virtual private cloud' where service providers host dedicated clouds for customers. Customers take advantage of tools, operational maturity and scalability that the service provider offers; however the underlying infrastructure is dedicated to only them. This model, particularly for Infrastructure-as-a-Service (IaaS), allows enterprises to get low cost, pay-as-you-use, flexible computing without the security, compliance and performance concerns of the public cloud, or the investment required to develop their own cloud infrastructure.

Many compelling pricing models offered by external cloud providers are actually not aligned to running production services 365 days a year; instead they are more suited to short-term bursts of resource such as retail, development or disaster recovery environments. This pricing structure lends itself to a hybrid model where organisations operate their own production infrastructures, only taking advantage of external clouds when required, on a temporary basis.

Cloud computing is service orientated, which means it is backed by service level agreements (SLAs). Perhaps the biggest concern enterprises have when evaluating the cloud is the SLAs the external service providers are committing to, especially in the ‘one size fits all' world that is the public cloud. Most SLAs are based on availability with little consideration to performance, a key requirement for enterprise IT infrastructure. As the public cloud grows and becomes more federated, many differing cloud solutions could form part of the supply chain making SLAs even harder to guarantee or track. Is this just another reason for enterprises to stay internal?

The cloud offers a vast number of solutions across a range of deployment models but organisations need to carefully align their requirements to the services offered by the external providers. In the long term, the push towards the commoditisation of IT services and benefits of scalability dictate that external cloud services may dominate. However, until the compliance, security and performance challenges are overcome; there will also be a market for private or hybrid clouds.

Tom Brand, cloud solutions service director at GlassHouse Technologies (UK).



« Basil Daniells (Middle East) - Five Challenges and Pitfalls of Implementing ERP in the Middle East


Matin Kaddour (Australia) - Data Loss Prevention within Australian Government Agencies »


Do you think your smartphone is making you a workaholic?