When adding larger drives to an existing RAID group of smaller drives, the larger drives will be right sized to match the usable capacity of the smaller drives. Adding a 10TB NL-SAS drive to an existi...When adding larger drives to an existing RAID group of smaller drives, the larger drives will be right sized to match the usable capacity of the smaller drives. Adding a 10TB NL-SAS drive to an existing RAID group of 4TB drives results in usable capacity of 3.63TB on the 10TB drive. If the right sized drive has partitions, follow How to replace a file system partition with a spare partition to move to a partition on a spare that is the correct size