For the original poster who goes by "IT Support"

To mount the drive (and since it is an external drive), once it's successfully formatted, make a directory such as /1tb to mount it when needed.

/bin/mkdir -p /1tb/notmounted

I use the -p so that you can make an additional subdirectory named "notmounted". This creates a mountpoint named "1tb" and you can mount it there. You can pick whatever directory name you wish of course.

After the drive is successfully created/formatted as explained by Christian and Sadashiva, you can mount it using the UUID or device name.

You can get the device name using the command fdisk -l and make note of the drive that seems to be 1tb in size, and with a device name that comes after your previously existing drives.

You can also run the command blkid and make note of the drive's "UUID" number. Let's say for the sake of discussion, your device name is /dev/sdb1 for your new external drive (it may certainly be different and the UUID will certainly be different).

 ~]# blkid
/dev/sdb1: UUID="7fa9c421-0054-4555-b0ca-b470a97a3d84" TYPE="ext4"

You can mount the drive using one of the below commands (again, your drive's UUID will be different).

/bin/ls /1tb
notmounted

This ls command above shows the sub-directory named notmounted which is in the path /1tb/notmounted if you used the suggestion I provided earlier

Now to mount it

mount UUID="7fa9c421-0054-4555-b0ca-b470a97a3d84"  /1tb
ls /1tb
Lost+Found

You will no longer see the subdirectory named notmounted after the drive successfully mounts

Alternatively you can use the device name to mount the drive, this assumes a device name of /dev/sdb1, it may be different on your system:

mount /dev/sdb1 /1tb
ls /1tb
Lost+Found

Diagnosing a failed mount

• Use the root account to perform any necessary partitioning,formatting, mount/umount commands.
• Pay attention to the output from commands that will give some clues to failed mount, such as "mount: mount point /1tb does not exist"
• Make sure you properly created the partitioned on the drive as explained earlier by Christian and Sadashiva
• Make sure you properly formatted the drive as explained earlier by Christian and Sadashiva
• Make sure you created a mount point (directory) using the /bin/mkdir command explained earlier.
• Make sure the external drive is plugged in to power, and is turned on if necessary
• If necessary, reboot the system so that the system can "see" the new partition and (only if necessary) redo the format as explained earlier by Christian and Sadashiva (if and only if the drive is not formatted)

• Using the blkid command will show active file systems, if you do not see your new drive you partitioned and formatted, you may need to revisit steps above.

• Come back here for assistance as needed, please let us know how it goes and thanks Christian and Sadashiva

Since this is an external drive, you probably do not want to make a persistent entry into your /etc/fstab file, but mount the drive as needed after connecting it to your system. (Note, a RHEL 7.x (current RHEL7 system ought to just "pick up" the external drive and mount it under /run/media/home/youruserid/[device_name_or_uuid] automatically)

Kind Regards, RJ