fdisk tells the disk is still NTFS, installation for RHEL7 tells its ext4?

Hello!

Strugling to install RHEL7 on my server and all is fine until I need to add more disks to it.
Have done ALL right when using fdisk and saves it with W, also the mkfs -t ext4 /dev/DISK.
Rebooting the server, run a check and the fdisk tells the disk is still HPFS/NTFS/exFAT, do a new install of RHEL7 and marks the large disk and reclaiming the space and this ones tells me the disk is ext4.

What is wrong? And what have I missed? Are doing a new install and will post the output later. :)

Cheers
Pontus