I just purchased a N7700 NAS. It is a 7 bays NAS. I would like to build multiple RAID Volumes. I would like to know the maximum RAID volume I can create on this machine. Is it better to use hard drives with the same capacity, or I can have some hard drives that has smaller capacity?
Depends on what kind of RAID you're building. If you're building RAID 1, it's best to use the same-sized drives. RAID 0 AFAIK works with any size discrepancy.