Script breaks after changing MTU on vmkernel being used to run script

[drwoodberry]

I am working on getting my old 5.5 scripts to work with our newish 6.5 environment. The scripts create several vSwitches on each host and enable jumbo frames on them, and this works with no issues. However, when I try to enable jumbo frames on vmk0 on vSwitch0 my script stops executing. When I log into the web interface I can see the MTU has been changed, but eventually the script times out. Making this change in 5.5 caused no issues with the script. Does anyone have any suggestions? I guess I could leave jumbo frames disabled, but the links for the management interfaces are just carved up bandwidth coming in from the 10GB trunks being used for the vDS and other vSwitches. Does it really make a difference if I have different MTU's on vSwitches even though everything is coming over the same links, just different NICs? These hosts are HP blades with the management NICs being on the Mezz cards and the other NICs coming from the internal NICs.

[LucD]

I assume the vmk0 is over a VSS, not a VDS.
Is your PowerCLI connection to the vCenter perhaps going over this vmk0?
Do you have this for all vmk on all VSS on all ESXi nodes?

I assume the code you use to change the MTU is using Set-VMHostNetworkADapter?

[drwoodberry]

All of your assumptions are correct below. Some additional information, I have two NICs for Management, and I noticed yesterday that one of them was down. I am going to try to resolve that issue and attempt again to modify.

[drwoodberry]

Got the other links to come up, still disconnects when changing MTU from 1500 to 9000. Not sure if there is a way around this or just how 6.5 is handling the change. I do not recall this being an issue in 5.5.

[LucD]

Are you sure your network (starting with the physical switches) is configured for jumbo frames end-to-end?