Jumbo frames let ESXi hosts send larger frames out onto the physical network. The network must support jumbo frames end-to-end that includes physical network adapters, physical switches, and storage devices.
Before enabling jumbo frames, check with your hardware vendor to ensure that your physical network adapter supports jumbo frames.
You can enable jumbo frames on a vSphere distributed switch or vSphere standard switch by changing the maximum transmission unit (MTU) to a value greater than 1280 bytes. With vCenter Server 7.0 Update 3, you can set the size of the maximum transmission unit (MTU) on a vSphere Distributed Switch to up to 9190 bytes to support switches with larger packet sizes.