Enabling Jumbo Frames with VMware ESX 4.x



This tutorial can be used to configure Jumbo Frames for either NFS or iSCSI.

Firstly all configuration for Jumbo Frames are done via the CLI.

To enable Jumbo Frames within VMware ESX you must first enable Jumbo Frames on the vSwitch with the following command.

[root@vmhost]# esxcfg-vswitch -m 9000

For Example

[root@vmhost]# esxcfg-vswitch -m 9000 vSwitch1

Next if you have already created a VMkernel port group you must remove it within vCenter. So make sure to vmotion the machines off or power them down before removing the port.

Now we’ll create a VMkernel port named VMwareNFS on vSwitch1

[root@vmhost]# esxcfg-vswitch -A VMwareNFS vSwitch1

You can optionally assign a VLAN tag to the VMkernel port, if you are sharing this physical NIC with other networks. The VLAN tag is specified after the -v in the example below. Here we are using vlan 10.

[root@vmhost]# esxcfg-vswitch -v 10 -p VMwareNFS vSwitch1

Last step is to configure the IP address of the VMkernel port along with the MTU size of 9000.

[root@vmhost]# esxcfg-vmknic -a -i -n -m 9000 -p VMwareNFS

After setting the MTU to 9000 on the VMkernel port you must reboot the host.

To verify that your settings are correct enter the following:

esxcfg-vmknic -l (Lists vmkernel info)

esxcfg-vswitch -l (Lists vswitch info)

All the tutorials included on this site are performed in a lab environment to simulate a real world production scenario. As everything is done to provide the most accurate steps to date, we take no responsibility if you implement any of these steps in a production environment.

  • Guest

    In ESXi 5 the MTU=9000 can be set directly from the VSphere client.