Example for Redhat 7.2
Assume a new disk was added as /dev/sdb and to be mounted as /backup
1. Use fdisk to partition the drive
eg. using the whole disk in one partition /dev/sdb1
2. format with the desired filesystem
# /sbin/mkfs -t ext2 /dev/sdb1
3. specific a label for this filesystem for use in fstab
# /sbin/e2label /dev/sdb1 /backup
4. add entries in :-
/etc/fstab
LABEL=/backup /backup ext2 defaults 1 2
/etc/mtab
/dev/sdb1 /backup ext2 rw 0 0