"Insufficient capacity on each physical CPU" error powering on a virtual machine

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• Attempting to power on a virtual machine fails with the error:
  
  DRS cannot find a host to power on or migrate the virtual machine
   
• Manually powering on the virtual machine fails with the error:
  
  vCenter was unable to find a suitable host to power on the virtual machine for the reasons listed below.
  • Description: DRS cannot find a host to power on or migrate the virtual machine
  • Description: Insufficient capacity on each physical CPU
     
• Selecting a resource pool during a migration displays the warning:
  
  Insufficient capacity on each physical CPU

• You see error messages for affinity rules.

 

Environment

VMware vCenter Server 6.x
VMware vCenter Server 7.x

Cause

This issue occurs when CPU reservation set on the virtual machine exceeds the physical CPU core capacity for the available ESXi hosts.

Resolution

To resolve this issue:

1. Calculate the maximum reservation value.
2. The formula for this is number of CPUs on the ESXi host, multiplied by number of available CPU cycles in GHz.

For example: A four CPU ESXi host runs at 2500 MHz. Maximum reservation would be: 2500 x 4 = 10000 a VM with a reservation of 10384 would not power on this ESXi host.

3. To resolve this issue:

• Reduce the reservation set on the virtual machine to less than the capacity of the pCPU on the host.
• Add more physical CPU resources to the ESXi cluster.

Additional Information

Virtual machine does not power on when there is high CPU reservation 
Failed to power on virtual machine