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Sebastia
Contributor
Contributor

is there a limit on how many VMs can be started with the system ?

Hi. We have a x3850 machine with ESX v4 opsys.

In it, there are 49 VMs, but I want only 26 to start with the machine.

So, I have 26 VMs in "Automatic startup", and the rest in "Manual startup".

But I see that only first 19 VMs start with the machine, and the rest do not.

I would like to know :

a) is there a (configuration) limit on the number of virtual machines that can be started with the ESX ?

b) is there any log describing this startup process, so I can try to investigate what went wrong ?

Thanks. Sebastian.

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5 Replies
Alistar
Expert
Expert

There shouldn't be any limit on the amount of VMs that can be running concurrently - at least there are none on ESXi5.x, but I can be wrong with ESX 4.

The place to look at are the log files which can be observed via an SSH session to the ESXi as a root. The logs to look for are the following in /var/log:

/var/log/vmkernel <- the log of VMkernel itself

/var/log/vmkwarning <- the warnings extracted from VMkernel are dumped there

/vmfs/volumes/<vmdatastoreUUID>/<vmname>/vmware.log <- the VM's log

To best way to observe what could be going wrong in the vmkernel is monitoring it in "real time" is to enter

tail -f /var/log/vmkernel

and trying to power on the 20th machine by yourself - there you will see the initialization process by itself.

Also, try investigating the 19th Machine if its VMware tools booted up - this is the safest measure for the boot-up chain to continue.

Stop by my blog if you'd like 🙂 I dabble in vSphere troubleshooting, PowerCLI scripting and NetApp storage - and I share my journeys at http://vmxp.wordpress.com/
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wila
Immortal
Immortal

Hi,

Maximums depend on the resources you assign to the VMs and resources of the host, but the  hard maximum is 320 VMs/host for vSphere 4.

See also: http://www.vmware.com/pdf/vsphere4/r40/vsp_40_config_max.pdf

cheers,

--

Wil

| Author of Vimalin. The virtual machine Backup app for VMware Fusion, VMware Workstation and Player |
| More info at vimalin.com | Twitter @wilva
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SebastiaNet
Contributor
Contributor

Sorry - it looks like I did not make myself clear enough.

The problem is NOT with the number of VM's to be running at a given moment.

The problem is in the number of the VMs to START, from the "Configuration" + "Virtial Machine Startup" list.

I want to start 26 VMs, but ESX only starts the first 19, then nothiung to the remaining 7.

mr Alistar : all machines start fine when manually.

The problem is only with the "power on" procedure.

I shall have a look into the logs ...

Thanks. Sebastian.

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wila
Immortal
Immortal

Hello,

As long as you have the resources it will start the VMs, there's no number limit on how many VMs will work in the auto-start list.

Starting manually is not exactly the same thing as using autostart.

Manually you most likely start them over a longer time period and the host has time to reclaim back the memory and disk, CPU is also be more active during boot.

--

Wil

| Author of Vimalin. The virtual machine Backup app for VMware Fusion, VMware Workstation and Player |
| More info at vimalin.com | Twitter @wilva
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SebastiaNet
Contributor
Contributor

I do understand that there sould be no limit on the number of machines in autostart list.

But my system has a problem with this list

How can I debug this problem ?

Sebastian.

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