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ESXI 4.1 Host draws HIGH CPU at Idle

Hello Expert Friends,
I manage a single ESXI host for a client and lately, (but maybe I did not notice it before) it is showing 50% CPU in the VI client when the system is totally idling. It is a IBM-Lenovo RD120 (M6447-18U) server running 12 VM's as Virtual Desktops. When a user logs in, performance is very poor and simply opening a browser window usually pegs CPU for a 30 seconds or more. Given is shows 50% usage totally idling (and all the VM's show nearly 0 CPU usage) makes me think there is a serious issue. Why would the CPU be so high when it is not taken by the VM's? All health parameters in the VI client logs are good.

THanks!
-John
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JohnnyD74
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JohnnyD74
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
what you do not state is the amount of memory in the host, memory assigned to 12VMs, high cpu usage is normal with a user login to desktop, if the datastore is slow or host is suffering memory starvation, and its paging swapping to disk.
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
have you tried Veeam Monitor for free to start checking all the performance metrics for the host and VMs, do VMs for instance use roaming profiles and or virus scanning.
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JohnnyD74Author Commented:
Hi Hanccoka,

I am running 20GB of memory on the host and 15K SAS RAID 5 array. The Key is that i am seeing 50% host CPU useage at IDLE with ABSOLUTELY 0 ACTIVITY ON TH VM'S. The VM's even show 0 CPU Useage....yet still the 50% Useage. I have a moderate about of experience with VMware and ESX and this is quite abnormal.

Thanks.
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JohnnyD74Author Commented:
Oh...and 2GB of memory are assigned to each winXP VM.
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
So if ALL the VMs are OFF, you have 50% CPU?

Memory in the VMs, OS in the VMs?
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
RAID 5 datastore is poor choice of RAID for Desktop VMs.
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
So 24GB memory assigned to VMs, on a 20GB host, so its over committed, by 4GB.
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JohnnyD74Author Commented:
Yes...I know, but that is what I have and not related to my CPU delema.
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JohnnyD74Author Commented:
Yes...correct on the memory numbers.
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JohnnyD74Author Commented:
No....I believe if they are off, the CPU goes down but the VI client shows near 0 useage for all VM's at Idle.
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
So, when powering up the VMs, one by one, when does 50% CPU occur?
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
I would suggest using Veeam Monitor for free to analyse the metrics.
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
also you state in the opening question, that you did not notice, what do the performance charts state for the year? has this always been the case, or has it just started occuring.
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JohnnyD74Author Commented:
When powering up the VM's Host CPU is at 100%....the 50% at Idle seems to illustrate the Issue and weakness of the CPU...and I don't believe it has always done this..
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Performance Chart History?
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
At Power-UP you are likely to hit 100% for a while, because of the over subscribbed RAM situation, because at power-up, ALL VMs will require 24GB for a moment of time, at this time the host will start using the paging file on the disk system, this action of disk swapping will cause high CPU for a while.

Veeam Monitor for free

If you want a quick tool, to help you with wanting to know all the individual elements, then I would suggest using Veeam Monitor Free Edition

Veeam Monitor leverages Veeam Business View™ to enable performance monitoring, alerting and reporting for virtual machine groups based on criteria such as business unit, department, location, purpose, service-level agreement or any other criteria you define. This ability to perform business-centric monitoring helps to identify the business impact of a virtual infrastructure’s performance and respond accordingly. It also allows you to configure flexible alerts based on known server type characteristics and the potential business impact of an outage for more granular service-level management. You can also create targeted reports showing only the data relevant to specific business units, departments or types of server.
More features

Source
http://www.veeam.com/esxi-monitoring-free.html.


If you want to get down and dirty with the servers, then I would recommend the following documents


Performance Monitoring and Analysis


Guest-based performance monitoring is an inaccurate and unhelpful means of evaluating performance in virtual deployments.  See Guest-based Performance Measurement for more inforamtion.  Monitoring and analysis of VMware ESX Server should be performed with esxtop and VirtualCenter.

esxtop is the tried-and-true means of collecting every performance stat  needed and making it available in a way that is conducive to analysis.  The best source of information on launching esxtop can be found in the Resource Management Guide (page 159).

1. Check and correct CPU utilization: CPU Performance Analysis and Monitoring

2. Identify memory bottlenecks and remove: Memory Performance Analysis and Monitoring

3. Characterize storage performance and correct: Storage Performance Analysis and Monitoring

4. Understand and improve the network utilization profile: Network Performance Analysis and Monitoring

Within each of these articles are techniques for using counters from  VirtualCenter and esxtop.  Information on those counters is provided in

vCenter Performance Counters
esxtop Performance Counters

Also, note that, while useless in collecting performance data, Perfmon  can help with analysis of large esxtop output files.  

Using Perfmon for esxtop-based Performance Analysis

The vSphere Client can indicate that VM network traffic is causing a 1 GB Ethernet adapter to have a 99% utilization rate. But strangely, it doesn't display which kind of traffic is going across the virtual networks, where it came from or where it's going.

To learn which traffic is going across a virtual network, there's another free tool for vSphere: Xangati for ESX, a virtual appliance that tracks conversations on the virtual network. It's great for troubleshooting any virtual network issue, analyzing virtual desktop infrastructure and correlating vCenter performance stats with virtual network stats.

http://xangati.com/try-it-free/ (free)
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JohnnyD74Author Commented:
Hi Hanccoka,

Sorry for my delay. I was out for awhile.THANK YOU for all the details. I understand the impact on startup but the the host CPU will hang at 50% utilization for HOURS ON END AND COSTANTLY with NO load at all. The office is closed on weekends and I have checked the CPU utilization on the weekends and it still is at 50%. I will check your suggestions and get back with you. Thanks Again!
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JohnnyD74Author Commented:
Thanks for all your help Hanccocka! I am still having the issue but with all your suggestions here, I am sure I will get to the bottom of things.
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