Error: "Insufficient capacity on each physical CPU"

Products

• VMware vCenter Server

Issue/Introduction

• 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, or when powering on a virtual machine, you receive the message:
  
  Insufficient capacity on each physical CPU
 
• You see error messages for affinity rules.

Environment

VMware vCenter Server 6.x
VMware vCenter Server 7.x
VMware vCenter Server 8.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

1. Reduce the reservation set on the virtual machine to less than the capacity of the pCPU on the host.
2. Or, add more physical CPU resources to the ESXi cluster.

 

Additional Information

To calculate the maximum reservation value:

1. The formula for this is number of CPUs on the ESXi host, multiplied by number of available CPU cycles in GHz.
   
   Example: A four CPU ESXi host at 2500 MHz. would have a  maximum reservation of 2500 x 4 = 10000 MHz. A VM with a reservation of 10384 would not power on this ESXi host.
    
2. Or, use vsish to view the available resources for reservations:

vsish -e get /sched/groups/4/stats/capacity
group-capacity {
cpu-reserved: 63800 MHZ       <==== Current resources already spoken for
cpu-unreserved: 62132 MHZ     <==== Available for reservation
mem-reserved:88716288 KB
mem-unreserved: 647780884 KB

See also:
Failed to power on virtual machine