Thursday, March 12, 2015

Does Virtualization = Better Performance?

I've had the opportunity to work on many VMware virtualization projects since fully embracing the technology back with the release of vSphere 4.0.  One of the common misconceptions I ran into is that when converting physical servers to run as virtual servers, we should expect to see better performance.  Otherwise, why would we do it, right?  “My buddy at Acme Co. said they can reboot all their virtual Windows servers in under 10 minutes – that used to take them over an hour!”

I’ll be the first to admit, I fell victim to this expectation as well back in the day (queue Wayne’s World Dream dissolve):

I remember setting up my first ‘virtual machine’.  I was not sure what to expect when I chose to ‘Power On’ this device.  I watched in absolute awe as the BIOS screen that I had grown so accustomed to flash before my eyes for a split second, POST completed, it was ready to load an 
OS…


Wait – what!?!

I had a hobby of building my own high-end gaming desktops at home for a while and they had never completed POST that quickly.  What trickery is this?  Surely once I install Windows XP on this VM it will bog down… nope, still beats the pants off of any physical machine I have worked with.

Well, it turned out that was my first lesson in virtualization that I can remember – virtualization involves layers of separation between the VM and the underlying hardware.  One of the benefits of this separation, no hardware checks required after Powering On a virtual machine!

It wasn't until later that I realized the one of the key benefits of going Virtual – utilization.  Better performance is often a perceived side effect and oftentimes it’s very real, especially for companies migrating off of old hardware onto Hosts and storage running on new hardware.  But consolidating a 30 server environment to just 3 or 4, that is where the true value surfaces.  Think of the savings on power, cooling, battery backup... even noise pollution! 

If a service or application requires a certain level of performance, it may be best to keep it on a physical server.  This provides it dedicated resources; it’s not sharing the compute or storage with other machines!  Can this be accomplished within a virtual environment?  Absolutely, and with it would come the benefits of being a virtual machine.  But for a true, performance-centric setup, dedicated resources is the way to go.

So when does one go Virtual and when do you stay Physical?  What kind of performance do I need?  Which is more cost effective?  Which is easier to manage?  Which offers more protection against failures?  How is backup and recovery handled?

As part of the Professional Services Team at GLC, these are just a handful of questions I work with every day and the answers vary greatly.  We work with you to discover your business needs and help prioritize them, provide perspective when needed, and set realistic expectations when working together on starting and finishing your IT project.

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