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VivekDhayalan
Contributor
Contributor

Maximum number of VMs in ESX

Can any one tell me how many number of VM can be used in ESX 3.5. Currently I am using Dell 2950. My system has the following specifications

16 GB --- RAM

8 x 1.999 GHz --- CPU

300 GB --- Hard disk.

I would like to have windows XP OS in VM. The VM also contains other softwares that support scripting and it contains some antivirus so that my system should not get affected.

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vickylotay
Contributor
Contributor

Maximum no. of Powered on VMs 128.

Registered VMs = 200

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VivekDhayalan
Contributor
Contributor

I am working with 24 VM powered on currently, but I have got alerts stating that I am running out of CPU utilization.

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AndreTheGiant
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Can any one tell me how many number of VM can be used in ESX 3.5.

I would like to have windows XP OS in VM

Windows XP can work very fine with 512 MB of vRAM and 1 vCPU.

With 16 GB RAM (and ESX memory management) you can reach at least 64 XP VM.

With 8 x 2 GHz core (and a medium-low CPU usage) you can reach 48 - 64 XP VM.

With a single disk you cannot do more that 10 - 20 VM (depending on I/O usage and disk space requirements).

You need more disks, and (if you want to optimize disk space) View Composer (that require VC).

Andre

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Andrew | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro
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VivekDhayalan
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I my system has multiple disk only. Even then I am getting alerts in VIC (Virtual Infrascture Client). But when I look the performance of ESX through top command I can see about 95% of my CPU is in Idle.

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VivekDhayalan
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AS you can see in the image my CPU idle is arround 95.8% but I have got alert for host CPU usage.

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AndreTheGiant
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AS you can see in the image my CPU idle is arround 95.8%

You are watching Service Console CPU utilization.

NOT vmkernel CPU utilization.

Use esxtop, or trust in VC information Smiley Wink

Andre

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Andrew | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro
VivekDhayalan
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Thanks for your information. As per your assumption you said we can have upto 64 VMs in ESX. But with 24 VM itself I am getting CPU utilization upto 98%. Is it possible for me to increase the number of VM above 24.

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AndreTheGiant
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But with 24 VM itself I am getting CPU utilization upto 98%.

All your VM have only 1 vCPU?

Probably you have some application (maybe antivirus) that are using a lot of CPU resources.

You can try to work with resource pool and create at least 2 different pool with different shares (share = priority level).

Andre

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Andrew | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro
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VivekDhayalan
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Yes all of my virtual machines have 1 VCPU.

But my individual CPU consumption in virtual machines are about 40 - 50 % only. This utilization countinues 24 x 7. In this scenario can increase VMs

verify the attachement for CPU utilization.

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AndreTheGiant
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But my individual CPU consumption in virtual machines are about 40 - 50 % only.

"Only"? Smiley Happy

You VM are very CPU intensitive.

In this case with 8 core you can just use 16 - 20 vCPU.

Andre

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Andrew | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro
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VivekDhayalan
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I mean to say 40 - 50 % (650 - 800 MHz) of CPU utilization is vCPU utilization. If we compare it to ESX CPU ( 8 x 1.99 Ghz = ~16000 MHz), 800 Mhz is around 5%.

My VMs are not CPU intensitive, I verified in Task Manager of VM and I found it's only using 5 - 10 % on a single virtual machine.

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AndreTheGiant
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I mean to say 40 - 50 % (650 - 800 MHz) of CPU utilization is vCPU utilization. If we compare it to ESX CPU ( 8 x 1.99 Ghz = ~16000 MHz), 800 Mhz is around 5%.

Ok, but this still mean max 20 VMs (5% x 20 = 100%).

Andre

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Andrew | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro
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VivekDhayalan
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you have said that

With 8 x 2 GHz core (and a medium-low CPU usage) you can reach 48 - 64 XP VM

is possible. Can I know whether you are running some programs in the virtual machine or it's an idle VM.

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AndreTheGiant
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With 8 x 2 GHz core (and a medium-low CPU usage) you can reach 48 - 64 XP VM

Low level CPU usage is 10% - 15% of a single core.

Not 5% of all the cores.

Andre

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Andrew | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro
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