How server virtualization works

Server virtualization works thanks to the hypervisor, software that allows multiple operating systems to run simultaneously on one physical server.

Running multiple OSes and applications as virtual machines (VMs) on a single host server opens the door to server consolidation, which is one of the many benefits of server virtualization. The hypervisor and its advanced features also lets you move workloads among different VMs, hosts and even data centers -- an obvious benefit for business continuity and disaster recovery.

In this webcast, executive editor Jo Maitland explains how server virtualization works and how it can help you address your organization's server consolidation and disaster recovery needs.

Read the full transcript from this video below:  How server virtualization works

Hello and welcome to our short web cast on how server virtualization works. I'm Jo Maitland, executive editor and will guide you through the next few slides on this topic. We'll take a quick look inside the technology and two of the primary use cases for it, namely, server consolidation and disaster recovery.

The traditional way of running an application was on a single server and operating system. This has always been an expensive way to do things, as each app required its own machine which was often underutilized from a performance standpoint and a waste of resources.

With the virtual way, the new way of doing things, this came along in the early 2000's, a technology layer known as a hyper-visor is able to carve up all the underlying resources, namely, CPU, memory, and an IO capacity amongst multiple applications. So now you can have multiple apps running on a single server and these are each on their own virtual machine.

This is a huge boon from a consolidation perspective and the cost savings are a no-brainier. Essentially instead of having one application per server you can now have multiple apps on one machine, which saves a huge amount on hardware resources.

So, typically, in a traditional server environment the utilization rates would be five to ten percent and with virtualization now your utilization goes up to 50 to 80 percent. Meaning essentially that you buy a lot less servers and also save money on power and cooling costs which are a huge issue for data centers these days.

Another advantage on the consolidation side, is the time it takes to provision new servers. So typically this could be anywhere from three months up to in many cases, if you are deploying a new enterprise app, up to a year. And now you can actually provision new servers in days and have new applications up and running in a week to two weeks, which is a huge boon.

Additionally, in the old environment you would have to, if you were starting up a new application or new servers, when an old machine comes off of a lease, you'd probably have to do this during the night or on weekends, now it's possible to migrate that virtual workload to a new machine with no down time. So the app stays up and running which is another big win with this technology. So server consolidation is a major piece of this.

The other big use case is disaster recovery. In the old school approach to DR you would have to have two sets of the same hardware in sync. Disaster would strike and you would have to have exactly the same hardware over at your second side in sync in terms of firmware and application version, operating system version, over at site two. So this is not only expensive from a hardware perspective but was a real management headache.

Now with virtualization the process can be entirely automated so instead of manually reconfiguring hardware, firmware, installing new OS, installing new operating systems, all these steps are essentially stored as data in a few files on a disk, and then these files can be recovered to any hardware over at your second site, without requiring any manual work, essentially the virtual machines are independent of the hardware underneath.

You literally send those VMDK files over and everything that you need is in there and the entire system, as long as you have protected those files through back-up or replication, you've protected your whole system essentially. Those are the two major use cases for this technology. If you have any questions on this introduction, please email me at [email protected] or our site editor, Colin Steele at [email protected] Thanks.

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