How to quickly find and resolve VMware ESX Server performance capacity bottlenecks with VKernel

Posted on January 8, 2009 by David Davis in VMware with

As a system administrator with growing demand on your servers you will eventually run into a capacity bottleneck in your CPU, RAM, Disk, or network. These performance issues can be difficult to identify and troubleshoot without a quality tool. For typical Windows servers, performance management tools can often be difficult to install, configure, and obtain necessary information out of.

Just like most Windows Admins, administrators of VMware ESX Server & VMware Infrastructure will eventually run into performance capacity bottlenecks. However, what will make life much easier for VMware virtualization administrators is the availability of the VKernel Capacity Bottleneck Analyzer. Because of this tool, virtualization administrators can quickly and easily identify the cause of performance issues and find out what is needed to resolve them. Even better the VKernel Capacity Bottleneck Analyzer can alert VMware admins that a performance issue is “about” to occur, before it actually happens.

Let’s find out more about the VKernel Capacity Bottleneck Analyzer…

What are the features of the VKernel Capacity Bottleneck Analyzer?

While I already had a basic idea of what the VKernel Capacity Bottleneck Analyzer was, I still wanted to learn more about it before I tried it out for myself. To do that, I clicked on the flash video on the VKernel homepage. Here is what it looked like:

I must say that I was impressed!

The Capacity Bottleneck Analyzer flash video was very professional and I learned a lot about the product. I might even say that the video was even a little entertaining! From this video, I learned this:

  • VKernel Capacity Bottleneck Analyzer (or vCBA as I will call it for the rest of this article) is the only certified VMware appliance to immediately identify and eliminate performance/capacity bottlenecks.
  • You can download a virtual appliance version of the software and easily import it into virtual center (I had mine up and running in 17 minutes, even with the 500MB download)
  • There is virtually no setup and within minutes, vCBA can tell you what kind of performance you are getting from your VMware infrastructure.
  • vCBA monitors current and future capacity, 24 hours per day, and alerts you to anything you need to be aware of.

Results are displayed using simply, easy to read, reports with arrows and colors indicating performance status.

Here are some of the questions that vCBA can answer for you:

  • What host, RP, or cluster will run out of capacity next? And, how many days before the capacity is maxed out?
  • Where are the bottlenecks in your VMware resource pools, clusters, or hosts?
  • As changes are made to improve performance, is performance getting better or worse?
  • How many more VMs can fit in a resource pool, cluster, or host?
  • Who are the biggest resource hogs in your VMware Infrastructure?
  • What is amount of total space and free space on your SAN LUNs?

Do you know the answers to these questions now? My bet is that, like me, you don’t, simply because it is too difficult to manually attempt to gather this information, even using the performance tools available in Virtual Center.

Wouldn’t it be amazing to answer these questions in minutes? Even better, wouldn’t it be amazing to be to know WHERE you will have performance issues, HOW LONG before they occur, and what you MUST DO to resolve them before they happen?

It almost sounds like a fortune teller that is too good to be true. Fortunately, it isn’t and VKernel offers a free 15 day evaluation of the VKernel Capacity Bottleneck Analyzer. You can have this remarkable VMware Infrastructure performance appliance up and running in your VMware Infrastructure in under 20 minutes. Let’s find out how…

How do I evaluate the VKernel Capacity Bottleneck Analzyer?

To evaluate the Capacity Bottleneck Analyzer, I went to and clicked on Downloads. I downloaded and installed the Capacity Bottleneck Analyzer Standard. To see how I downloaded and install the Capacity Bottleneck Analyzer, step by step, see my article entitled How to download, install, and evaluate the VKernel Capacity Bottleneck Analyzer.


In that article, I cover the process of identifying the proper version to download, installing the appliance, and configuring the Capacity Bottleneck Analyzer for the first use.

How did the VKernel Capacity Bottleneck Analyzer help me?

I have a complex VMware Infrastructure with 6 ESX Servers and over 70+ virtual guests. I need a tool to help me manage the performance of this complex virtual datacenter.

I spent some time researching and understanding how VKernel Capacity Bottleneck Analyzer could help me manage my performance and help me find trouble, before trouble finds me.

Here are some screenshots from my evaluation.

Below, you can see how when I click on a single VMware ESX Server, I get a performance summary, showing the current performance status for that server. For example, it shows that performance usage is trending up at 71%. It tells me that I could put an estimated number of “2” more VM guests on this ESX Server. How else would I know this? It says that in the next 3 days I will have a memory performance problem and that the VM guest “exchangemb1” is taking the most resource of this physical host. WOW!

In the graphic below, I graphed the network utilization of this physical ESX Server host system. Its very easy to see what the busiest time was for the ESX Server. This versatile graph can show CPU, memory, storage, and network utilization for days, weeks, or months. Additionally, it can show these stats for ESX hosts, resource pools, or clusters.

In the graphic below, I look at the same summary overview but for an entire VMware Infrastructure resource pool. This screen tells me that storage it trending up in this RP and that I should be able to get up to 69 more VM guests in this resource pool. Additionally, in 6 days it says that I will have a problem with memory utilization.

The graphic below shows the same type of resource capacity and bottleneck analysis for an entire VM cluster of ESX Servers.

And finally, the graphic below, shows me the CPU utilization summary for the entire VMware ESX Server cluster. This graph is highly configurable and can be saved, printed, or exported to

In my opinion, the two best features of the Capacity Bottleneck Analyzer are 1) the ability to predict trouble before it happens and 2) the power to visualize the performance of my entire VMware Infrastructure in only minutes. I have seen no other tool for VMware Infrastructure can that do this!

In Summary

The VKernel Capacity Bottleneck Analyzer is a crucial third party performance tool. It is so easy to download, install, configure, and evaluate. I was impressed at how quickly and easily it learned about my VMware Infrastructure and was able to, almost immediately, tell me where the bottleneck was in what to do with it. Additionally, it could even predict how many virtual guests I could add, when I would have my next performance issue and where. Amazing! I highly recommend that you try out the VKernel Capacity Bottleneck Analyzer for your self by evaluating it today!

If you haven’t read my first article in this series, I suggest reading How to download, install, and evaluate the VKernel Capacity Bottleneck Analyzer.

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