As a response to the current economic climate, many organisations are turning to IT consolidation in an effort to cut costs, with virtualisation as one of the fundamental technologies underpinning these projects, writes Christo Briedenhann, regional director: Africa at Riverbed.

Setting up a consolidated infrastructure based on virtualisation simplifies administrative efforts and improves resource utilisation and data protection. Nevertheless, for organisations with distributed staff and a wide area network (WAN), virtualisation remains a real challenge.
When consolidating an information system, IT managers must consider application performance and data availability. Care must be taken not to resolve one problem while creating others, since the investment necessary for damage repair might cost more than any savings made.
The first challenge revolves around application performance. The rise of the decentralised computing model was largely driven by the need to keep IT resources closer to the distributed user base to achieve the best possible performance. Consolidating servers from remote sites reverses this distribution and, consequently, many applications suffer severe performance degradation after consolidation.
To remedy these performance problems, organisations often want to upgrade bandwidth in an effort to improve application response times. Instead, CIOs often discover that upgrading bandwidth to remote sites has little or no effect on application performance, because the performance problem lies instead with latency and application protocol inefficiencies across the WAN. In addition, the cost of bandwidth upgrades can often offset a significant portion of any cost saving achieved from IT consolidation.
The second consideration is the increased reliance on all of the centralised IT assets. Because the infrastructure is serving more users per physical piece of hardware, the requirements for system and data availability go up dramatically.
In addition, site consolidations limit the geographical diversity of IT operations and subject businesses to the risk of a site or regional outage. While server virtualisation can help greatly reduce the amount of time required to redeploy servers in the event of a failure, it does not necessarily protect against site failures, data loss or corruption.
Therefore, building a comprehensive disaster recovery and business continuity strategy has become critical for enterprises adopting a consolidated infrastructure. Consequently, IT departments are increasingly turning to technologies such as data replication and continuous data protection (CDP) to remote sites along with virtual tape library (VTL) for disc-to-disc backup operations
For most organisations, IT infrastructure consolidation presents a major opportunity to cut costs, but the degradation in application performance creates a significant trade-off that can result in some applications becoming unusable over the WAN. In these scenarios, organisations must decide to either forego consolidation efforts or run the risk of crippling the end-user experience. In some cases, companies have embarked on a consolidation project only to have it come to a halt due to the adverse impact on business applications and end-users.
Organisations seeking to fully realise the benefits of consolidation must ensure real-time access to applications and data for their end-users. WAN optimisation solutions help businesses that have centralised their computing environment, address this problem by delivering LAN-like performance for applications over the WAN.
WAN optimisation enables LAN-like access to virtualised infrastructure for users regardless of location. It accelerates the performance of all TCP applications running over the WAN by addressing the three primary issues namely bandwidth constraints, TCP latency, and application chattiness.
WAN optimisation overcomes performance issues in four ways:
* Reducing the volume of data sent and freeing up bandwidth by eliminating redundant data;
* Reducing TCP latency and chattiness by decreasing the number of roundtrips required to transmit data;
* Accelerating strategic applications by using specific optimisation modules; and
* Simplifying control and management by automating provisioning tasks and providing advanced reporting tools.
The ultimate goal is to provide users with fast and secure access to their data and applications through the virtualised infrastructure, regardless of where they are based in relation to the data centre. Therefore, access to the most "common" applications will be optimised – file-sharing, email, content management systems for collaborative workspaces, web applications, design documents, product lifecycle management solutions and ERP applications.
WAN optimisation is also often a requirement for a successful disaster recovery plan. WAN optimisation shortens backup and replication windows and maximises the available bandwidth between the sites, while at the same time avoiding congestion with other application traffic.
Infrastructure virtualisation and consolidation can offer significant advantages for both IT services and enterprise operations. Although the advantages are obvious, enterprises should always consider the specific requirements of their operations in terms of performance and availability.
A combination of WAN optimisation solutions and virtualisation offers IT managers a unique opportunity to facilitate their IT operations in a strategic manner and improve service delivery, while also saving money. IT managers would be well advised to consider these two technologies as key in their IT infrastructure.