VMware Enabling Jumbo Frames VMKernel

For NFS and ISCSI Usage it is recommended to run larger frames, also called Jumbo Frames.

Be sure to only change the behaviour if your Switch, Storage and Infrastructure supports Jumbo Frames and you know what you are doing

1. Create a new VSwitch which should contain the VMKernel (the following examples expect it to be named vSwitch1)
2. Change the Switch MTU to 9000

   esxcfg-vswitch -m 9000 vSwitch1
   

3. Check that the new size is used

   esxcfg-vswitch -l
   
   Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks   
   vSwitch1       64          3           64                9000    vmnic1    
   

4. Check that the NIC MTU has changed

   esxcfg-nics -l
   
   Name    PCI      Driver      Link Speed     Duplex MAC Address       MTU    Description                   
   vmnic0  02:00.00 bnx2        Up   1000Mbps  Full   00:26:b9:84:f7:c7 1500   Broadcom Corporation Broadcom NetXtreme II BCM5716 1000Base-T
   vmnic1  02:00.01 bnx2        Up   1000Mbps  Full   00:26:b9:84:f7:c8 9000   Broadcom Corporation Broadcom NetXtreme II BCM5716 1000Base-T
   

5. Add a port group (we will give it the name IPStorage)

   esxcfg-vswitch -A IPStorage vSwitch1
   

6. Finally add the port to the newly created port group (10.10.200.2 is the VMK IP)

   esxcfg-vmknic -a -i 10.10.200.2 -n 255.255.255.0 -m 9000 -p IPStorage
   

7. Check that you can use larger packets (10.10.200.101 is the storage device you try to reach)

   vmkping -s 9000 -v 10.10.200.101

This is not an official approach by VMware, Jumbo Frames are not officially supported for VMKernel