Hello, AFAIK cow images are currently not configurable via GUI and cannot be set as default disk format. IIRC the reason being RAW and sparse are providing better performance (until you try to copy a larger disk image...). However, you can add qcow - disks with ovirt shell and use these images: $ add disk \ --vm-identifier <vm_name> \ --provisioned_size <size_in_bytes> \ --interface virtio \ --name <disk_name> \ --format cow \ --sparse true \ --storage_domains-storage_domain storage_domain.name=<storage_domain_name> On 04.02.2015 18:56, shimano wrote: -- Daniel Helgenberger m box bewegtbild GmbH P: +49/30/2408781-22 F: +49/30/2408781-10 ACKERSTR. 19 D-10115 BERLIN www.m-box.de www.monkeymen.tv Geschäftsführer: Martin Retschitzegger / Michaela Göllner Handeslregister: Amtsgericht Charlottenburg / HRB 112767