Wanted to make a quick post about enabling Jumbo Frames in my VMware environment! My switches (Cisco SG-200 & SG-500) support Jumbo Frames so I thought why not? It would surely help push more data through the network for faster for VSAN and vMotions. I’ll do some speed tests later to compare!
Before you start out on this quest ensure your physical switch support jumbo frames. When enabling it on my Cisco switches a switch reboot was required:
The next step is to ensure the NICs in your servers support jumbo frames. If they are server NICs then they should. My Dell T620/R520 both have Broadcom NetXtreme 5709 which in fact support Jumbo Frames.
Enable Jumbo Frames on Virtual Switch:
Now that you confirmed you can physically support Jumbo Frames your ready to enable it in vSphere. If you are using Distributed Switches right click the vDS then Edit Settings:
On the Properties tab click Advanced. In the Maximum MTU box change it from 1500 to 9000 then click Ok:
For Standard Switches: Go to vSphere Standard Switch -> Properties -> with vSwitch selected click Edit -> then change MTU to 9000:
Enable Jumbo Frames on VMKernel:
Now that the switch supports up Jumbo Frames let’s enable it on a vmk virtual adapter. Go to one of your hosts -> Configuration -> Networking -> vSphere Distributed Switch -> Manage Virtual Adapters -> Select a vmk -> Edit:
Check if Jumbo Frames are working:
If you have the VSAN health check enabled it does a health check on MTU size:
If the computer your on has Jumbo Frames enabled you can also perform a ping test. Open a command window and type:
ping -l 9000 <IP ADDRESS>