How To Format HDD

We have 2 HDD ,

HD1( sda) : 1 TB
HD2 (sdb): TB

when i check

Code:
# fdisk -l

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 121601 976655610 83 Linux

Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sdb1 * 1 1044 8385898+ 82 Linux swap / Solaris
it seems we must format sdb and mount to server
when i run this command :

Code:
mkfs.ext3 /dev/sdb1
result:

Code:
# mkfs.ext3 /dev/sdb1
mke2fs 1.39 (29-May-2006)
/dev/sdb1 is mounted; will not make a filesystem here!
after , i check

Code:
# nano /etc/fstab

Code:
LABEL=/ / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
LABEL=SWAP-sdb1 swap swap defaults 0 0
??

now ho can active sdb ?