Unable to modify NSX Edge VM resource reservation: "Insufficient capacity on each physical CPU"
Article ID: 443517
Updated On:
Products
Issue/Introduction
- This article provides a resolution for the error "Insufficient capacity on each physical CPU" encountered when attempting to modify or increase the CPU resource reservation for a VMware NSX Edge VM. The issue typically occurs when the per-vCPU MHz reservation exceeds the physical clock speed of the ESXi host's CPU cores. The article outlines how to validate available host capacity using vsish commands and provides guidance on aligning VM reservations with physical hardware capabilities to maintain maximum performance.
- When changing or increasing the resource reservation for an NSX Edge VM (e.g., following performance best practices to set 100% reservation), the vCenter task fails with the following error:
Error: Insufficient capacity on each physical CPU
Task: Reconfigure virtual machine
Description: Insufficient capacity on each physical CPU.The host [Host-Name] cannot satisfy requested [Value] MHz per vCPU for this VM. Maximum core frequency is [Value] MHz per physical CPU.
Environment
VMware NSX
Cause
This issue occurs when the CPU reservation (MHz) requested for a single vCPU exceeds the maximum physical core frequency (clock speed) of the ESXi host's CPU.
For example, if an Edge VM is configured to request 2100 MHz per vCPU, but the physical host's cores are clocked at 2095 MHz, the reservation cannot be satisfied because a single vCPU cannot be backed by more than 100% of a single physical core's frequency.
Resolution
To resolve this issue, use one of the following methods:
Method 1: Adjust Reservation via NSX Manager
For auto-deployed NSX Edge appliances, adjust the resource allocation from the NSX Manager UI to a value that is less than or equal to the physical core frequency of the ESXi hosts in the cluster.
Method 2: Identify Available Host Resources
Verify the current reservations on the ESXi host to determine available capacity:
- Log in to the ESXi host via SSH.
- Run the following command:
vsish -e get /sched/groups/4/stats/capacity - Note the cpu-unreserved value to ensure sufficient aggregate resources are available.
Method 3: Scale Hardware
Migrate the Edge VMs to an ESXi cluster with higher physical core frequencies or add hosts with compatible CPU specifications to the existing cluster.
Impact/Risks
Reducing the reservation below 100% may impact the maximum performance throughput of the NSX Edge appliance. It is recommended to align physical hardware with the Edge form factor requirements for production environments.
Additional Information
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