OK! I figured out a workaround.
Since adding a vmkernel interface remotely doesn't seem to work with DVS, I simply created one on a standard vSwitch and then migrated it to the DVS. And voila: the MTU set to 9000 migrated intact with it! Here are the steps I followed:
1. Put the ESX Host in maintenance mode - evacuate VMs manually if necessary
2. Remove the iSCSI/NFS VMKernel interface from the DVS
3. Create a standard virtual switch with no physical adapters. It does not need to be a VMKernel switch VM Networking is fine. Make a note of the name you gave to the PortGroup created on the new vSwitch.
4. Using the remote command line, add the new vkernel interface specifying an appropriate jumbo MTU (9000) and the PortGroup on the new standard vSwitch. For example:
esxcfg-vmknic.pl --server
If you get 3 replies, everything works. If you get failures, something went awry. Go back and verify the interface is configured properly using the esxcfg-vmknic.pl --list command.
Enjoy!
M
