How To Guy

Importance of vSphere Design: How To Figure Out Cluster Workloads

Nifty tips in Scott Lowe's new training video from TrainSignal

Enterprises pay consulting companies with vSphere design experience thousands of dollars to properly design and architect their vSphere infrastructures. If they don't, the results can be unreliable and poorly performing applications, application slowness, and even downtime. So, proper vSphere design is imperative.

The difficulty with design is that learning it is hard because there is rarely a "right answer." Instead, anytime you ask a question about design, the answer is usually "it depends" or "it's complicated." Typically, the only way to learn to design vSphere infrastructure is to actually design one. It's been a challenging subject to teach others to do and the best way to do it is to use "scenarios" based around fictitious companies.

Recently, I saw a great example of "design in action." While watching Scott Lowe's new Designing VMware Infrastructures video training course, he talks about how to calculate total cluster workloads.

He starts off with my favorite fictitous company, the Wired Brain Coffee Co. (which I have used in all my training videos), talking about how they have approximately 500 workloads that require 468Ghz, 714GB of RAM, 57 IOPS with 62% read and 32% write, 48GB of storage capacity, and 75 Mbps.

From there, he says "you're going to use servers with 16 cores at 2.2Ghz/core and 96GB of RAM. How many of those servers do you need?"

It's a tough question to answer! As Scott works through it, he talks about how we also much account for some headroom on the cluster. In other words, we want to size it at about 80 percent (not 100 percent) of utilization. With that, if the answer you came up with is 17, then you are right (just so you know, I didn't come up with that number so fast). Scott, in the video, walked me through the math that you would use, as well as helping to characterize the workload of the applications.

Whether or not you just want to obtain the VMware VCAP-DCD certification (datacenter design) or just want to obtain real-world vSphere design knowledge for your company (or especially if you work for a consulting partner), Scott has some great information on the topic.

For those who don't know, Scott has the VCDX certification and is the author of the most popular vSphere book, Mastering vSphere. He's also been blogging for a long time here.

As for Scott's VMware Design course from TrainSignal, I watched the course myself as part of the review process and learned a lot. Here's a full lesson from the course on YouTube.

For those interested in achieving the recently released VCAP-DCD on vSphere 5, you should know that a VCP5 is required but no other training is required by VMware to take the exam.

About the Author

David Davis is a well-known virtualization and cloud computing expert, author, speaker, and analyst. David’s library of popular video training courses can be found at To contact David about his speaking schedule and his latest project, go to


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