Could a latent flaw in the Boeing 737 be discovered, grounding the entire Southwest fleet?  Sure, it's a risk.  But I'd be willing to bet dollars to doughnuts that the folks over at Southwest would tell you the benefits far outweigh that risk.

Back to virtualization.  Taking a single vendor approach to virtualization can help you streamline operations in many of the same ways that Southwest was able to streamline operations with Boeing.  Having more than one vendor within any given virtualization genre adds complexity.  And the irony of it is you would be adding the kind of complexity you were trying to free yourself from by virtualizing in the first place.  I think much of the multi-vendor argument hinges on the assumption that workloads can be easily moved between virtualization vendors.  Yeah, this can't really be done today, at least not without a major effort and downtime.  Granted, there are projects in progress that will allow a VM built on one hypervisor to run on all hypervisors.  But there is so much more to running and managing a virtual infrastructure than simply being able to power on a virtual machine.  It would likely take longer and be more painful to move workloads between the two different vendor environments than if you just fixed whatever forced you to move the workloads in the first place.

 The second argument

This one is about cost.  It's almost always targeted at VMware, and it usually sounds something like this, "Why pay the high cost for VMware for my entire infrastructure?  Why not just pay the high costs for my applications that absolutely need it and use the cheap stuff for everything else?"

Why I Disagree

Well, this one is easy to refute.  VMware has a tiered pricing model.  Why not pay for the enterprise license for the apps that need it and then pay for a less expensive license for everything else?  Or if you're looking for really cheap, ESXi is free and it's hard to get cheaper than that.  Don't let anyone fool you, ESXi is the full hypervisor, the exact same hypervisor that the most expensive version of ESX comes with.

Now you do lose a lot of features with the free version of ESXi.  But what's to stop you from using Powershell (also free) to reclaim some of that lost functionality?  A fantastic example of this is a Powershell script written by Mike DiPetrillo that you can find at his blog in a post Quick Migration for VMware - The Power of Powershell.  His script (free to download), gives you the ability to do a quick migration of a VM from one ESXi host to another.  And if you combine this with PowerGUI (also free), you could run this script by simply right-clicking on the VM you want to migrate.  Shoot, what's to stop you from creating a number of scripts like these and manage all of your free ESXi hosts from within PowerGUI?  The point is, if you want to go with VMware as your vendor but can't afford the price tag for all your servers, you've got plenty of options.

I'm going to bring this article to a close for now.  Feel free to comment or send me an email if you'd like to debate about the matter a bit.  For now, I'm going to go see if Dr. Phil is still sucking his thumb.

VMware , Aaron Sweemer Blog