MSDOS MBR Partition Tables make it impossible to use Partitions larger than 2 TiB. This is a pitfall you maybe will be faced with after expension of a RAID array. The only solution is to convert the MBR Partition Table to GPT (GUID Partition Table).
This can be done quite easily by using GPT fdisk.
GPT fdisk includes the sgdisk program which can convert MBR Partition Tables to GUID Partition Tables using the following command:
sgdisk -g device
(for example sgdisk -g /dev/sda)
Warning: doing this will make your system unbootable as there’s no longer a master boot record existing.
The BIOS Boot Partition replaces the MBR. Make sure you have enough unused space to create it.