Create partition larger than 3TB under GNU/Linux

You may need to create partition larger than about 3TB under GNU/Linux, with recent Hard Disk Drives having great capacity, with RAID configuration ...
Usually to create/manage partition with command line under GNU/Linux, fdisk is very adapted and powerful, but it is unable to create partition greater than 2/3TB (according to version, and architecture ?), because it needs to manage GPT partition (not supported by fdisk).
For that, you can use GNU Parted which is another powerful tool.

Instead of long explanation, this is a concrete example creating a 4TB partition on a RAID 10 (let's call it /dev/md16):
To begin, activate the GPT:
parted /dev/md126 mklabel gpt

Then, create a primary partition with all spaces (4TB):
parted /dev/md126 mkpart primary ext4 0 100%

Finally, formats it (for instance with ext4 and default block size):
mkfs.ext4 -v /dev/md126p1

Manage Intel RAID under GNU/Linux using mdadm tool

You may be interesting to read some history about RAID first.
This article is about managing Intel RAID, with mdadm tool, but some information may apply to others kinds.
To begin, you can find lots of information about RAID under GNU/Linux.

IMPORTANT: for Intel's IMSM support you need at least

RAID 10 on Intel ICH10R under GNU/Linux (including HDD devices on Marvell 88SE9128)

After my experience to setup a RAID 0 on Intel ICH10R Vs Marvell 88SE9128; I've recently experienced the setup of

Some history about Intel RAID under GNU/Linux (dmraid/mdadm)

Although RAID is supported under GNU/Linux since many years, it is not trivial either.
This article is about Intel RAID, but some information may apply to others kinds.

There is at least two tools allowing to manage RAID devices: