So lets say you have a server with 2x hard disks. after the install quickbox is using only one disk how to make it use the other one as well.
QuickBox is more than likely only utilizing one of the disk due to your RAID configuration. You will need to setup your server in a RAID 0 configuration to have it read the total cumulative space of both disks.
There is a FAQ for this on the FAQs page of the site.