I knew from the product docs that Jumbo Frames were supported, but had a tough time figuring out how to enable them. A quick call to tech support and I was all sorted out, so I thought I'd share and save anyone else the trouble.
Log in via console > enable > configure terminal > SYSTEM MTU <size>
Just plug in the MTU size you need and this should enable jumbo frames up to that size for the entire switch. I believe these support frames up to 13000, but don't quote me on that.
EDIT: While jumbo frames on your connected devices typically use an MTU of 9000, in order for the frames to properly flow across the NetVanta without truncation you will need to increase the size slightly to allow for packet overhead. Once I bumped the NetVanta System MTU to 9216, I had no more issues.