Converting from raw to qcow2

[plight]

Hello. I have a 120gb raw image of a disk and I am converting it to qcow to run via proxmox. The process outlined in the wiki works perfect. But I am curious, exactly how does it convert the image to qcow?

The reason I am asking is because the size of the raw partition is 120 gigs, after converted, the size is around 62 gigs. There is only 12 gigs worth of data on the image. Why can it not compress it (during conversion) to less than 62 gigs? it seems to handle to majority of white space just fine.

Thanks in advance.

 

[dietmar]

There is only 12 gigs worth of data on the image. Why can it not compress it (during conversion) to less than 62 gigs

Because there is no way to detect unused data (obviously there is unused data which is not zero).