Last week I mentioned that I had not yet said much about virtualisation. With the recent announcements surrounding the national broadband network (NBN) it is time to start thinking about the infrastructure for the future and building systems now that will see us through the next few years while the politics and reality of the NBN plays out.
First we need to ask; why virtualise at all?
There can be only one answer to this in the current climate - to save money. If you will not save or make more money through virtualisation, now is not the time to do it.
Other drivers for virtualisation include reduced power and cooling requirements, space reduction, hardware consolidation, lessened environmental impact and an added layer of management that improves flexibility - letting you shift servers from one hardware platform to another with little effort and no downtime, for example.
Next let's address who should or could virtualise?
If you are a small business with one or two servers, virtualisation is probably not going to give you much more than headaches. If you need three or more servers there are possible cost savings, depending on which technologies you select. If you have significantly more than six servers there are likely to be considerable savings available to you.
What are the benefits that lead to a reduction in cost?
The cost savings come from both a reduction in the number of physical servers required and more efficient use of the existing resources and thus a reduction of capital expenditure. The reason the hardware is used more efficiently is that a single server is typically only busy for brief time "slices" and spends most of its time in an idle state or relatively unused. Typically each server has access to its own storage resources and these too are only partially used, leaving spare capacity.
Virtualisation software can better manage the resources of processor, memory and storage to keep a number of servers busy a higher percentage of the time. Multiple operating systems (OSs) can then be run simultaneously on a single hardware platform. They can be different OSs such as Windows and Linux, or different versions of Windows, and so on.
For a business with an application that requires Windows 2000 and no plans to support Windows 2003 or 2008 server, this can be a blessing as maintenance of a separate hardware platform is no longer required.
With multiple OSs on a single box, it is possible to have a large array of hard drives attached and have the virtualised servers share the storage as required with only minimal slack space across the set.
Similarly one physical server can have multiple processors and "time share" the processor resources. All this leads to a smaller physical footprint, lower total energy required, and less investment in aging hardware.
Once your organisation has multiple physical servers hosting multiple virtual servers, it is possible to set up fail-over options, whereby a virtual server can be moved from one physical box to another and automatically restarted in the case of a hardware failure.
There are many other benefits to virtualisation that I will discuss in the future as well as looking at options offered by the three major technology providers in this space.
If you have specific questions on virtualisation please add them in the comments below and I will address them.
David Markus is the founder of Melbourne's IT services company Combo. His focus is on big picture thinking to create value in IT systems for the SME sector.
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