migrating non proxmox openvz container to proxmox 4

[cquest]

I have an old openvz based setup which I want to migrate to proxmox 4 (and LXC).

I've backuped a test VM using vzdump, but when I restore on my proxmox 4 node, I get the following:

root# pct restore 101 vzdump-openvz-101-2016_02_21-15_40_41.tar
unable to create image: qemu-img: Image size must be less than 8 EiB!

It looks like pct restore think it is qemu instead of openvz ?

 

[cquest]

After some more investigation, it looks like my old vzdump (1.2.x) does not create a dump file compatible with today's pct restore...

How can I do some conversion ?