Error on editing VM: "A specified parameter was not correct: spec.memoryAllocation" or "A specified parameter was not correct: spec.cpuAllocation" after adjusting sched.cpu.latencySensitivity on VMX.

Products

• VMware vSphere ESXi

Issue/Introduction

Error can happen on trying to power on a virtual machine after manually adjusting the Advanced Parameter "sched.cpu.latencySensitivity" as "high".

The task of "Reconfigure virtual machine" if attempted to set CPU reservation will return this full error:

• "A specified parameter was not correct: spec.cpuAllocation The latency-sensitive virtual machine must have the CPU reservation set to at least ##### MHz (the number of low latency virtual CPUs multiplied by the measured physical CPU speed). To disable this check, set latency.enforceCpuMin to FALSE in the virtual machine configuration."
  
  or
  
  
• "A specified parameter was not correct: spec.memoryAllocation The latency-sensitive virtual machine must have the memory reservation set to the memory size."

The task "Reconfigure virtual machine" can also fail with the same error if no changes are made, only opening Edit Settings then click "Ok"

 

Environment

ESXi 8.0 U2 and later with VM hardware version 21

Cause

This can happen if the parameter is set manually by changing the "sched.cpu.latencySensitivity" using the "Advanced Parameters" or editing the VMX file directly.

 

Resolution

1. Change the "sched.cpu.latencySensitivity" back as "normal" using the correct method:
   1. Edit Settings
   2. VM Options
   3. Advanced
   4. Latency Sensitivity: Normal
   5. Ok
      
      
2. Change it again as "high" using the same method observing the requirements for CPU reservation with high sensitivity as per Performance Tuning for Latency-Sensitive Workloads.:
   1. Edit Settings
   2. VM Options
   3. Advanced
   4. Latency Sensitivity: Normal
   5. Ok
      
      
3. Change the other settings related to the CPU and memory reservation accordingly.

1.