About OVF (Open Virtualization Format)
It is an open standard used across different virtualization platform. An OVF virtual machine consists of a directory containing virtual machine files and a file describing them.
About OVA (Open Virtualization Appliance)
It is a single compressed file containing the contents of an OVF directory.
VMware OVF tool
VMware OVF tool is a command line utility that supports import and export of OVF packages to and from vSphere infrastructure.
Download Tool – http://communities.vmware.com/community/vmtn/server/vsphere/automationtools/ovfDocumentation – http://www.vmware.com/support/developer/ovf/
ExportC:\Program Files\VMware\VMware OVF Tool>ovftool.exe "vi://username:password@vCenterIP:443/DataCenter_Name/vm/Demo-W7-VM" "C:\VM-Backup\Demo-W7-VM.ova"
ImportC:\Program Files\VMware\VMware OVF Tool>ovftool.exe "--datastore=datastore1" "--network=VM-Network" "C:\VM-Backup\Demo-W7-VM.ova" "vi://username:password@vCenterIP/DataCenter_Name/host/Cluster_Name/hostIP"