VMs can cost more than physical servers -- really!!

I am amazed how many virtual environments I have now seen that are severely under utilizing the new hardware and are afraid to increase VM density. They buy expensive server hardware, loaded it with 16Gigs or more for $30K to $50K and are running just a handful of VMs on it. This is analogous to driving a perfectly good Ferrari without ever getting out of first gear!! Say your are running 8 Vms on a $50K hardware. Add the cost of SANs, etc and you can quickly see how the cost of each VM can actually be higher than the physical server it replaced. This of course begs the question why do people underutilize the hardware?

As far as I can tell there are several reasons. Some are just being utilization "ignorant" about their environment, but the majority is simply afraid to "push the metal" and increase utilization because of concerns about running into ESX performance problems or worth yet -- downtime. Since finding capacity bottlenecks using Virtual Center is not trivial and time consuming, and predicting future capacity bottlenecks requires fairly advanced mathematical analysis of all core 4 resource types , disk I/O etc, most Vmware Admins lack the time and experience to do this exercise. So they keep the Ferrari in first gear, keep driving blindfolded, and hope that vm sprawl does not catch up with them. With availability of tools like the Vkernel Capacity Bottleneck Analyzer
VMware admins will gain visibility into current and future capacity problems and steer clear of performance issues. It heps driving with lights on!! Tell us what you think www.vkernel.com

Want awesome performance in VMWARE ESX?

Of course! we all do! So let's talk about how to get there. To achieve stellar VMware ESX performance you have to remove ALL bottlenecks in your environment. Remember your performance will only be as fast as the slowest "link" in your performance equation.

Here is the list to start removing performance bottlenecks:

1. Make sure that all of your hosts have sufficient RAM and do not over commit on memory utilization. If your workloads force the host to start swapping memory to disk, kiss your performance goodbye. There is a huge difference in speed between accessing memory internally and doing physical i/o to disk!

2. Make sure your CPU is not over utilized. Checks the processor ready queue to see how long threads are waiting to run. Extended period of time indicates a problem. Also check the overall processor utilization over a week or a month. Keep the overall utilization under 80%

3. As you scale up your ESX environment you will run into disk i/o bottlenecks. Make sure that you places your most mission critical VMs on the fastest storage available to you

4. Understand the timing of your workloads to identify when or if constraints develop in memory utilization, cpu, and disk i/o. Spread out the workloads by changing when they run i.e timing or move workloads to different hosts to mix it up.

How to predict future capacity bottlenecks

Your virtual data center is growing. You are adding a ton of new VMs every week. Wouldn't it be really cool if you head a "crystal ball" that told you in how many days you will run into capacity bottlenecks and what type of bottlenecks it will be (cpu, memory, storage) ?

Now you can. Join Vkernel's beta program for Capacity Bottleneck Analyzer that will kick off in early March

How many new VMs are you adding per week?

How many new VMs are you adding per week? This is very important question, because it has major implication to capacity availability in your ESX data center and ultimately performance. Every VM you deploy will consume cpu, memory, storage and network resources. It will also add additional disk I/O. It is easy to see how, if uncontrolled, you can quickly run out of resources and develop capacity bottlenecks. Of course the trick is to figure out which resource you are going to run out of first? Will you hit the bottleneck in memory, cpu, storage, disk i/o or network? The answer is it really depends on your environment, but in most cases the first bottleneck is memory. Why? Remember you were able to virtualize servers, because they were under utilizing CPU. That is what enabled you to combine 8+ plus servers on one piece of hardware. When you think about memory, it is a different story. Just because your servers are now virtual, it does not mean they are consuming less memory. Hence that's why in most environments the first capacity bottleneck is memory. What do you think the second capacity bottleneck you are likely to hit? Let me know at abakman@vkernel.com

9 capacity bottlenecks in ESX that kill performance

I have compiled a list of "things" that can cause you to run out of capacity resources in your ESX data center and run into performance problems or even downtime:

1. Adding new VMs though uncontrolled VM sprawl
2. Removing hosts from clusters
3. HA enabling your cluster without accounting for fail over
4. Changing Fail Over Capacity setting in a Cluster
5. Increasing reservations in VMs
6. Changing Resource Pool Configurations
7. Power up many VMs that were powered off or in maintenance
8. Natural growth rates in Storage, CPU, Memory and Network utilization
9. Changes in workloads can result in Disk I/O bottlenecks

Did I miss any? Let me know abakman@vkernel.com