An administrator has been tasked with configuring virtual switches and setting the appropriate MTU size for a Nutanix cluster to optimize network…

Enabling jumbo frames (MTU of 9000) requires an end-to-end configuration across the entire network path. The process must begin with the underlying physical network infrastructure. If the physical switches are not configured to support the larger MTU size, any jumbo frames sent from the Nutanix hosts will be dropped or fragmented, leading to severe performance degradation or complete connectivity loss. Therefore, configuring the physical switches is the foundational and prerequisite step before modifying any settings within the Nutanix AHV hosts, CVMs, or user VMs. This ensures the physical transport layer is prepared to handle the increased packet size.

A. Configure the MTU on the user VMs.

This is a later step. Configuring VMs first without preparing the underlying virtual and physical network will cause their jumbo frame packets to be dropped.

B. Configure the MTU on the Controller VMs (CVMs).

This is also incorrect. The CVMs rely on the same host and physical network stack, which must be configured for jumbo frames first to ensure storage traffic is not disrupted.

C. Configure the MTU on the virtual switch in Prism Element.

This step configures the host's virtual networking, but it must be preceded by configuring the physical switches to which the host's physical NICs connect.

1. Nutanix University - Nutanix Hybrid Cloud Fundamentals Courseware: In the networking module, the principle of end-to-end MTU consistency is emphasized. The courseware explains that network configuration starts from the physical layer (switches) and moves up to the hypervisor and virtual machines to ensure compatibility.

2. Nutanix AHV Networking Best Practices Guide: In the section "Jumbo Frames," the guide states, "To use jumbo frames, you must configure the physical network, all the AHV hosts, and all the UVMs for jumbo frames." This implies a specific order, starting with the physical network as the foundation.

3. Prism Web Console Guide (for AOS 6.5): In the "Network Management" section, under "Managing a Virtual Switch (AHV)", the procedure for setting the MTU on a virtual switch is detailed. This action assumes the upstream physical network devices are already configured to support the desired MTU. The guide focuses on the Nutanix-level configuration, which is dependent on the external physical network configuration.