VMware Optimization Questions

We're having some issues right-sizing our VMs. I've ran reports with Veeam ONE Reporter as well as looked at ESXTOP.

The problem we're having is that when we reduce CPU and memory overhead to what the reports suggest, the user experience suffers. If we increase resources, even though they aren't using the resources, the experience improves. I understand that guest OS and host performance stats are different and that the guest will report higher.

Do you guys have any tips on right-sizing VMs?

Thanks

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Comments

Essendon

Can we take a look at a part of the report with the company info hidden? Did you run the report after you made the changes and what did you change? What are people using and what are the VMs running? This should get us started on giving you tips. There could be a myriad of factors to this issue.

matai

This is some pieces from a report ran prior to re-sizing.

This is a summary of the report:

This is one page from the CPU section:

This is one page from the RAM section:

If I were to follow this guide, some of the Windows 7 virtual desktops would be running 1 vCPU and 1GB or under RAM. Does this seem like too little for office work with dual monitors?

Thanks

Summary.JPG

CPU.jpg

RAM.jpg

Essendon

Could be under spec'd for some office users (what do they run? Office, Lync etc). Other thing is the cumulative effect of lowering the CPU's on all of those VMs may be what's affecting performance. What's the interval Veeam looks at before generating these recommendations? Is it instantaneous or from data collected over a period of time? Does it affect all users or only some people using certain software? I'm sorry but you're going to have to narrow it down a bit yourself.

azjag

If I were to follow this guide, some of the Windows 7 virtual desktops would be running 1 vCPU and 1GB or under RAM. Does this seem like too little for office work with dual monitors?

The answer to this is it depends. Yes you can get away with 1vCPU and 1gb of ram if you have a really streamlined Win7 desktop and users that only use office and browse the internet. We keep all of our win7/8 desktops at 2vCPU's and 2gb of ram for task workers and only increase the memory when they start using more applications. This tends to be the best combination as long as we are not over-allocating our CPU/Memory.

Keep in mind the workload of the host as well. The ability to run multiple vCPU's without performance issues is very dependent on the kinds of workloads that are being supported. If the host is supporting lots of virtual machines, each with only meager processing needs, you won't have an issue. If, however, the host is running a number of processor intensive workloads, you may need to adjust your vm to host ratio or reduce the vCPU's.

Metrics to Watch
• Inside virtual machines
o CPU Utilization- This metric will allow you to make a determination about when it’s time to add an additional vCPU to a virtual machine. It’s time to add an additional vCPU to a virtual machine when average CPU usage remains running at high levels.
• On the host
o CPU Ready - From an overall host health standpoint with regard to CPU, this metric is, by far, the most important gauge. CPU Ready is a metric used to determine the length of time that a virtual machine is waiting for enough physical processors to become available in order to meet the demands of the virtual machine. If a virtual machine is allocated four vCPUs, this metric will indicate the length of time that the virtual machine waited for four corresponding pCPUs to become available at the same time.
o CPU Utilization - The overall CPU usage on the host server is also critical as it allows you to understand just how much work the host server is doing.

I did chuckle when I saw it recommended giving a SQL server 1vCPU and 1.3gb of ram. Grain of salt recommendations.