how to mount disk that larger than 2TB

1. install the tool like gpart
# apt-get install gpart

2. confirm the disk lable you want to format
# fidsk /dev/sdx

3. use gpart tool to make a partition
#gpart /dev/sdx

make a partition label for it, we use gpt that support larger disk size
(parted) mklabel gpt

Warning: The existing disk label on /dev/sdx will be destroyed and all data on this disk will be lost. Do you want to continue?
Yes/No? yes

set the unit
(parted) unit TB

create 3TB size
(parted) mkpart primary 0.00TB 3.00TB

(parted) quit

4. format the disk
#mkfs.ext4 /dev/sdx

5. mount it
#mkdir /mnt/backup
#mount /dev/sdx1 /mnt/backup

6. use df to confirm the disk size
#df -h