Virtualization - What is it and how does it help your Business?
In simple terms virtualization allows you to partition a servers processors, storage and memory into two or more systems in effect creating a completely autonomous virtual server (VM) that can run a standard version of one or more operating systems such as Microsoft Windows or practically any flavour of Linux. A piece of software called a hypervisor (Microsoft Hyper-V, VMware, Cirtix XenServer and others) together with the latest advances in on-chip technology allows us to use a lot more memory than was previously possible enabling more powerful virtual servers to be created. How does this help? Virtualization can help in a number of ways:
- Reduced server count - In enterprises where large numbers of users are supported then virtualizing a number of these servers to run on a host server reduces the floor/rack space required as well as power and cooling requirements and of course reducing cost !
- Better Redundancy - By clustering two physical servers together it is possible to provide highly available virtual server hosts reducing downtime and requiring much less hardware than was previously required.
- Disaster Recovery - Physical servers need to interact with the physical hardware making them harder to move between physical systems. As virtual servers do not have the same reliance on the physical system they are portable and can be easily exported and installed on another Virtual Host significantly reducing the time required to recover a system.
- Application Separation - In the past running many applications on a single server was a common practice to try to realise the full performance available from the physical system. However, this was not always desirable as resource hungry applications may not live well together. Virtualization allows us to separate these applications even on the same piece of hardware without impacting other systems.
- Legacy Applications - As most of the popular operating environments can be presented as a virtual server then it is possible to deploy legacy applications on more up to date hardware.
Virtualization Deployment Facts
Virtualization can solve many problems for your company or organisation but it also brings some new challenges and complexity. The following outlines some of the issues that I have encountered whilst deploying virtualized environments.
Software and Licence Cost - Remember each virtual server that you wish to run will most likely require a licence, particularly Windows Server and Desktop platforms. This is less of an issue if you will run Opensource environments such as Linux.
Hardware Cost - Virtualization requires physical servers with more powerful CPU with lots of cores, more memory and lots of storage.
Additional Hardware - USB, local Tape and other more exotic hardware will require special consideration as they are likely not to be directly supported.
Choose your Hypervisor - All of the vendors provide their hypervisor either as part of the operating system or provide a free hypervisor. However these offerings come with limitations (Windows Standard limits the amount of memory that can be used and the free VMware hypervisor limits the size of virtual disks)
Management and Education - New tools and training will be required for IT or Admin staff particularly in sites with many virtual servers.
Your backup methodology will need an overhaul - Although Virtual Server technology allows us to use greatly improved backup and recovery techniques
Expectation - Virtualization is perceived to automatically "make everything go faster" this is obviously not the case and whilst virtualization can solve many IT issues, careful planning is required to be able to achieve capacity and performance goals.