There are two common problems when creating partitions in Linux on big storage arrays.

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.

The second problem is this warning from parted:

(parted) mklabel gpt
(parted) mkpart primary 0 100%
Warning: The resulting partition is not properly aligned for best performance.

Solution: Use percentage sign for the partition start point, instead of an exact units in Mb or Gb.

For example, it should work if you use

mkpart primary 0% 20GB

Also, parted has the option optimous that should automatically align for best performance when using percentages:

parted -a opt /dev/sdb mktable gpt
parted -a opt /dev/sdb mkpart primary 0% 100%