I want to add a 4TB hard disk drive for data storage only. My current configuration: Questions : Because the size is greater than 2TB am I really forced to use GPT partition? If yes, GPT partition required UEFI or legacy BIOS is supported? if legacy bios is supported, Arch Linux will see 4TB or 2TB only? This new hard disk drive is for data only and I will not install OS on it or boot from it. Answer I'm the author of the GPT fdisk partitioning software, so I know this subject pretty well. Previous answers have promoted some misconceptions that I'd like to address.... If you want a partition size greater than 2TB, you must use GPT instead of MBR. Probably. The catch is that that MBR maxes out at 2^32 sectors. This translates to 2 TiB (not 2 TB; see here for an explanation of the difference) if the logical sector size is 512 bytes. Many external disks and a few internal disks now use 4 KiB (4096-byte) logical sectors, though, which raises the MBR limit to 16 TiB. Note that...