### Human: Can you tell about Enabling Jumbo MTU on AHV for UVMs. ### Assistant: This article describes how to enable jumbo MTU on AHV for UVMs.. Nutanix Controller VMs (CVMs) use the standard Ethernet MTU (maximum transmission unit) of 1,500 bytes for all the network interfaces by default. The standard 1,500-byte MTU delivers excellent performance and stability. Nutanix does not support configuring the MTU on a CVM's network interfaces to higher values.You can enable jumbo frames (MTU of 9,000 bytes) on the physical network interfaces of AHV, ESXi, or Hyper-V hosts and user VMs if the applications on your user VMs require them. If you use jumbo frames on hypervisor hosts, enable them end to end in the desired network and consider both the physical and virtual network infrastructure impacted by the change.. PreparationMake sure that the following changes are implemented before making any changes:

The physical L2 switches must be configured to support a 9000-byte Ethernet payload and any additional network overhead such as VLAN tags and VXLAN encapsulation. This means the switching infrastructure is often configured to support a maximum MTU of 9216 bytes, larger than the endpoint MTU.Any routed L3 interfaces between networks must also be configured to support the larger MTU.
Consult the documentation of your network vendor for this configuration. Only after the entire physical network is ready to handle jumbo frames between all endpoints can we configure our Nutanix AHV hosts.

Check the current network configurationTo check the current host network configuration, connect to the CVM you will be making changes on and run the following command:

nutanix@cvm$ manage_ovs show_uplinks

Sample output:

nutanix@cvm$ manage_ovs show_uplinks

One of the main items we want to check at this step is the bond_mode. If balance-slb or balance-tcp (LACP) modes are used, restore this configuration after making the MTU changes.

Next, connect to the AHV host and verify the current MTU value of the physical interfaces. These typically show up as ethX, but may vary depending on the hardware in use.

nutanix@cvm$ manage_ovs show_uplinks

 

Change MTU (AOS 5.19 and newer)

Refer to the Prism Web Console Guide for your appropriate AOS version for instructions on how to update your Cluster Virtual Switch's MTU.

Login Prism > Settings > Network Configuration > Virtual Switch > Edit Virtual Switch
	
	Set the MTU and Save the Update (MTU on Nutanix Host must be set to a value in 1500 ~ 9000 inclusive range)
	
	
Change MTU (AOS 5.18 and older)Perform the following steps on every host in the cluster that needs these changes.
Connect to the host using the IPMI console and log in to the AHV host as root.Log on to the Controller VM via SSH to the management address.
	nutanix@cvm$ manage_ovs show_uplinks
	Put the node and CVM in maintenance mode. Refer to Putting a node into maintenance mode chapter from AHV Administration Guide for more details.Run the following command to enable jumbo frames on the interfaces.
	nutanix@cvm$ manage_ovs show_uplinks
	where <bond mode> equals one of the following modes: active-backup, balance-slb or balance-tcp. The current bond_mode can be found in the output of the manage_ovs show_uplinks command. If --bond_mode parameter is not specified, then the bond mode will be reset to active-passive, which may affect network connectivity.	Note: In the above command the syntax "--mtu 9000" or "--mtu=9000" are both valid.If LACP is used then a few more additional parameters should be added:
	nutanix@cvm$ manage_ovs show_uplinks

	Example:

	nutanix@cvm$ manage_ovs show_uplinks

	If a bridge other than br0 is used for UVMs, the configuration should be similar to the following example:

	nutanix@cvm$ manage_ovs show_uplinks

	The above example applies to configuration with and without backplane network segmentation, as it only changes MTU of physical NICs without touching interface br0, or interface br1-backplane if configured.		Note: --require_link=false is only required if any physical NIC is down while configuring, which you can check with manage_ovs show_interfaces.
	WARNINGS:

	On clusters running any AOS release between 5.10 and 5.10.3.2 DO NOT run "update_uplinks" with a single interface specified as this may impact cluster availability. If you have a node with a single interface in bridge, upgrade AOS to 5.10.4 or newer, or engage Nutanix Support if you want to change the bond configuration.Updating uplinks using manage_ovs will delete and recreate the bond with the default configuration.The use of the allssh manage_ovs update_uplinks command may lead to a cluster outage. Only use it if a cluster is not in production and has no user VMs running.
	If balance-slb or balance-tcp (LACP) modes were used, then refer to the following KB articles to restore the configuration. Otherwise, if LACP is not enabled, go directly to step 7:
	balance-slb: KB 5135balance-tcp (LACP): KB 3263
	Gracefully shut down the Controller VM on this host:
	nutanix@cvm$ manage_ovs show_uplinks
	Reboot the AHV host.
	nutanix@cvm$ manage_ovs show_uplinks
	Once the configuration is completed, make sure both host and CVM are accessible via network.If all tests are successfully completed, remove CVM and node from maintenance mode. Refer to Exiting a node from the maintenance mode chapter from AHV Administration Guide for more details.Create a VM network.
	nutanix@cvm$ manage_ovs show_uplinks
	Enable jumbo MTU inside UVM guest OS.Test the reachability of the jumbo frame between UVMs.	Linux:
	nutanix@cvm$ manage_ovs show_uplinks
	Windows:

	nutanix@cvm$ manage_ovs show_uplinks

	Note: "-M" and "-f" are to set df-bit (don't fragment), and 8972 is ICMP data size, which equals 9000B (MTU size) - 20B (IP header) - 8B (ICMP header). There are another 14 bytes/18 bytes for Ethernet header (6B source MAC + 6B destination MAC + 2B ethertype + 4B VLAN tag (VLAN tag is optional)), which are not part of MTU size. Therefore, the maximum frame size allowed after the above configuration is 9014B/9018B (with VLAN tag).
	. ### Human: Now explain this as a Nutanix support agent summarizing the answer step by step. In case, you don't know the answer say - I don't know.