There are two common problems when creating partitions in Linux on big storage arrays. The first is easy, and the warning message from fdisk is a bit of a giveaway:
WARNING: The size of this disk is 8.0 TB (7970004230144 bytes). DOS partition table format can not be used on drives for volumes larger than (2199023255040 bytes) for 512-byte sectors. Use parted(1) and GUID partition table format (GPT).
The answer: use parted. Don’t have it? Install it!