Server Virtualization – To Deploy or Not To Deploy

Source – Public Domain, 2003

In keeping with the contemporary mindset of doing more with less, server vendors and integration specialists are touting the virtues of Server Virtualization as the key to consolidation salvation. To the uninitiated, server virtualization is the consolidation of server resources in a way that hides the physical and technological boundaries so that it appears seamless and integrated to resource users.

To an organization’s system administrators, life just got easier on two fronts. Virtualization technologies make it easier to consolidate to bigger servers. At the same time, virtualization makes it easier to re-provision and manage smaller distributed servers. This is good news for enterprises which have had to over-provision their servers to handle the unpredictable peaky workload demands stemming from Internet access.

Technical Opportunities for Server Virtualization

There are several areas where an enterprise can leverage server virtualization:

• Operating Systems – virtualization can be applied in a number of ways in the OS layer, such as between an application and the OS, between the OS and hardware components such as partitions, and across multiple operating systems and fixed hardware.
• Workload Management – at present, workload management can be a real headache when the enterprise has both Unix and Windows architectures, each of which expects to control certain files and resources. Server Virtualizations which isolate applications in their consolidations will help solve the resource contention problem.
• Distributed Workloads – Virtualizations can allow workloads to run concurrently across multiple OS instances, thereby balancing consumption. For distributed sequential workloads such as a service with Web servers, application, and database servers, a virtualization distributed workload manager can take over the management of each OS instance as a combined entity.

Virtualization Pros and Cons

As an enterprise, do you or do you not proceed with a Server Virtualization Deployment? There are strong arguments in favor of it. The first one is money. You must have at least a minimum level of server virtualization, for example, to host multiple web sites on a single server instead of having dedicated machines for each website, at multiples of the sever costs. The same can be true of development shops, which can save a bundle in server hardware costs by running server virtualization to host multiple development areas.

That being said, there are some situations where an enterprise may have business requirements that may be compromised by having server virtualization. Say for example you were hosting a number of mission critical sites on a single server. If that virtualized server went down for some reason, all the hosted sites would fail. Another situation involves the distributed workload mentioned above. A virtualized server’s workload manager may balance consumption and demand on resources initially, but what happens if one of those consumers grows into a resource hog? Then the other application users become marginalized and suffer degraded performance.

There are ways around all of these issues, but the point is not to consider the cost advantage as the only decision driver.