[ovirt-users] P2V shrink disk

Hi, I am not sure if it's the right place to post this question. I tried to do a P2V operation of a Win2k3 server to ovirt 3.5 the physical server is RAID5 of 3x146Go configured, about 290 Go usable space, but the server uses about 20Go only. I am wondering how to shrink the disk of the migrated physical machine, do I have to do it before using P2V tool? The same question for Linux servers. Thanks.