The last oVirt 4.3 release contains a bug which will export OVAs with empty disks. Just do
a du -h <ova-filename> to see if it contains more than the XML header and tons of
zeros.
Hopefully the orignal VMs are still with you because you'll need to fix the python
code that does the export: It's a single line of code that needs to be added.
https://bugzilla.redhat.com/show_bug.cgi?id=1813028
It's a bit of a nasty surprise, when you've relied on OVA export/import as the
most primitve operation for a hypervisor, especially before a migration.
While the bug was fixed for 4.4 in March or earlier, it didn't make it into the last
4.3 release... you have the source, after all.
The deprecated export domain seems to work across the 4.3 to 4.4 gap, even if they are
still deprecated on 4.4 and their handling is nowhere as flexible as OVA files.
My understanding of the developer's opinion is that OVA is really just an import
facility for all those VMware machines you want to migrate to oVirt. Nothing you'd
ever want to use for anything else, especially not for the other direction.
I consider the ability to export an important management VM like a IAS as an OVA and be
able to run it on say a virtualbox, a potential life saver, especially when a farm got
lost in a 4.3 to 4.4 migration.
Not that I am planning that any longer...