Difference between OVA and OVF

An OVF is a collection of items in a single folder. Most commonly

this is a description file (.ovf) a manifest file (.mf), and virtual

machine state files (*.vhd or *.vmdk)

   

An OVA is a single file.

The OVA is the OVF folder contents all zipped into a single file. The

purpose of the OVA is when you want to take an OVF and share it, or give

it as a download. The OVA needs to be opened into the OVF before it can

be consumed.

ESX / ESXi Version

As shown in the documentation, the OVA is used when your ESX or ESXi hosts are version 4.0 or later while the OVF is used for 3.5: