[Libguestfs] Extracting files from OVA is bad

Hi, recently we (oVirt) have started discussing whether the way virt-v2v handles import from OVA files is good. And I would be interested in ideas how it can be improved. It is likely somebody already gave some thought to this problem. TL;DR: Extracting the OVA before import is a problem for large VMs (in sizes of TBs). Can we change something to prevent the extraction and work directly over OVA? What we consider a huge shortcoming is the fact that whole OVA is extracted prior to the import into a temporary directory and processed afterwards. Under normal situation user can have up to three copies of the VM on his drive at the end of import: * original OVA, * temporary extracted files (will be deleted when virt-v2v terminates, * converted VM. This is not a good idea for large VMs that have hunderds of GBs or even TBs in size. The requirements on the necessary storage space can be lessened with proper partitioning. I.e. source OVA and converted VM don't end up on the same drive and TMPDIR is set to put even temporary files somewhere else. But this is not a general solution. And sometimes the necessary space may not be available at all. The question is how to change the import path so that virt-v2v doesn't have to extract the OVA. I can see the following solutions: 1) Solve it virt-v2v: create a layer for directly accessing the files in the archive. 2) Solve it in QEMU: create backing method that would allow creating qemu disk backed by the archive. 3) Solve it on oVirt side: use some FUSE-based tool to provide access to the archive and pass the OVA to virt-v2v not as a file but as directory. Does anyone have any other ideas or suggestions? Best regards, Tomas Golembiovsky -- Tomáš Golembiovský <tgolembi(a)redhat.com&gt;