Virtualizing servers is a process which hides the actual server resources from the users. The number of physical servers and their individual details, relating to processors, storage, operating systems and so on, are combined into a single large virtual environment. Using server virtualization software allows individual applications to be run in their own separate environments on the same machine. As an example you could have both Windows and Linux systems running together on a single system. This allows you to save space, minimise complexity, cut energy costs and gain greater flexibility in the use of resources.
Server virtualization can help get the most from the resources of a single server. At the same time it reduces the risk of a server crash and can help with faster recovery in the event of a problem. It allows a business to operate with fewer physical servers by consolidating its systems. Ultimately this leads to lower costs through reduced staff time, maintenance, cooling and energy consumption. This introduction to server virtualization explains the challenges and benefits involved.
The Five Key Challenges to Server Virtualization
Undertaking a move to virtual servers is a major exercise and a step that enterprises may be reluctant to take unless they can be sure it’s going to benefit them.
The trend towards virtual servers is gaining pace, but there are some key concerns that must be addressed before making the investment in server virtualization. The following should help address these areas.
1. Budget issues
Managers often claim that they don’t have the budget to be able to invest in server virtualization. It can be hard to justify any expenditure when budgets are under pressure, but you need to consider that the best time to undertake a virtualisation project is when the department is renewing or upgrading existing hardware. If you’re spending money anyway it makes sense to look to the long term efficiency you can achieve.
2. Costs vs ROI
Because servers are sometimes seen as intangible assets, and virtualizing them makes them even more so, management can be sceptical that it will see a return on its investment. The key here is to recognise that physical servers often operate below their true capacity, sometimes running at as little as 20 per cent. The company may therefore be paying the full up-front and maintenance costs for something that it isn’t fully realising its potential.
3. Educating the IT department
Adopting server virtualization will very often see an enterprise having to reassess how its IT department operates. This should always be seen as a positive opportunity rather than a cost. A change to virtual servers gives a chance for the IT department to reduce its routine workload and take the opportunity to make more informed contributions to higher level initiatives.
4. Security and control concerns
Adopting virtualized servers is likely to give some managers a sense that they’re in some way losing control. Businesses need reassurance that they’re getting the right service levels and that they retain the degree of control they’d have with an in-house system. There are often concerns about sensitive data being moved to less secure environments. There are also worries surrounding the ‘hypervisors’ needed to manage virtual servers, as they may have levels of operator privilege that allow for abuse or amplify the effect of errors.
While it’s true that server virtualisation does introduce control and security challenges, there is plenty of help available to address these concerns. Companies need to work closely with their vendors to make sure that they have controls and best practices in place to deliver the reassurance they need.
5. Migration and other systems
One of the potential problems with virtualisation is a ‘server storage gap’ that arises when virtual machines serve up too many applications at one time, leading to high demand from I/O processes. Companies often discover that they have many more operating system instances than they did before adopting a virtual environment.
Migration of virtual machines (VMs) can also be a complicated process. Converting virtual to physical servers requires a number of tools and processes, and can be handled manually or automatically. Manual migration runs the risk of introducing errors, as well as being time consuming, so in most cases companies will opt to employ some sort of migration tool. Even so, a successful migration depends upon careful planning and a clear understanding of the existing infrastructure.
Testing shouldn’t be neglected either, it’s critical not just to determining virtual machine capacity, but also to ensuring that applications continue to work in the new environment.
Many companies won’t have the expertise in-house to undertake server virtualisation, or will be unsure as to which package of tools to use. It’s therefore always best to seek out expert advice.
Is Server Virtualization for You?
If your business has multiple physical servers they can almost certainly benefit from virtualisation, even if it’s a relatively small organisation. If you have more than three physical servers, then any time you’re thinking about changing or upgrading a server you should think about virtualisation too. It could be just as cost effective to virtualize all of your servers at the same time as it would be to do only one.
Other occasions when considering a switch to virtual servers is worthwhile include the point at which you’re updating hardware, switching or updating applications, or revising disaster recovery and business continuity plans.
Checklist for Server Virtualization
Look at how your physical servers are currently used and work out how much capacity you’ll need in a virtual environment. This will avoid you ending up with more virtualisation than the hardware can handle.
Thoroughly test all the applications you’ll be using on the virtual environment before implementing. This helps to ensure that they will work correctly and will identify any resource intensive applications that may require multiple servers.
Take time to understand the licensing terms for virtualized servers. It’s important to understand that virtualizing on site won’t reduce your licensing costs, but if you opt to use a hosting service you will probably see some reductions as server license fees will be transferred to the hosting service under their SLA.
Understand and address security and compliance concerns; these should be among the top priorities when switching to a virtual server environment.
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