Unable to format new mountpoint

Can some one help me i try to mkfs new mountpoint from storageIBM but give some problem

[root@ ~]# mkfs -t ext3 /dev/sdd1
mke2fs 1.39 (29-May-2006)
/dev/sdd1 is apparently in use by the system; will not make a filesystem here!

my os is redhat 5.3

using fdisk

[root@ ~]# fdisk -l

Disk /dev/sda: 298.9 GB, 298999349248 bytes
255 heads, 63 sectors/track, 36351 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        2550    20482843+  83  Linux
/dev/sda2            2551        4590    16386300   82  Linux swap / Solaris
/dev/sda3            4591        5865    10241437+  83  Linux
/dev/sda4            5866       36351   244878795    5  Extended
/dev/sda5            5866        7140    10241406   83  Linux
/dev/sda6            7141        8415    10241406   83  Linux
/dev/sda7            8416        9690    10241406   83  Linux
/dev/sda8            9691       36351   214154451   83  Linux

Disk /dev/sdd: 536.8 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1       65270   524281243+  83  Linux

Disk /dev/sde: 536.8 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sde1               1       65270   524281243+  83  Linux

Disk /dev/sdh: 536.8 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdh1               1       65270   524281243+  83  Linux

Disk /dev/sdi: 536.8 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdi1               1       65270   524281243+  83  Linux

Disk /dev/dm-0: 536.8 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

     Device Boot      Start         End      Blocks   Id  System
/dev/dm-0p1               1       65270   524281243+  83  Linux

Disk /dev/dm-1: 536.8 GB, 536863993344 bytes
255 heads, 63 sectors/track, 65269 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/dm-1 doesn't contain a valid partition table
[root@ ~]#

so it's already being used. please show output from mount

when i check mount don't see new mounpoint

[root@ ~]# mount
/dev/sda1 on / type ext3 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/sda8 on /u01 type ext3 (rw)
/dev/sda7 on /usr type ext3 (rw)
/dev/sda6 on /tmp type ext3 (rw)
/dev/sda5 on /opt type ext3 (rw)
/dev/sda3 on /var type ext3 (rw)
tmpfs on /dev/shm type tmpfs (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
[root@ ~]#

Then maybe it is already a part of your software raid (dm-0 or dm-1) ?

thank all !, i alredy success
have one lun add on server
[root@ ~]# multipath -l
mpath1 (360080e50002c085e00006d924fc314aa) dm-0 IBM,1814 FAStT
[size=500G][features=0][hwhandler=0][rw]
and
(vi /etc/multipath.conf) add wwid LUN with alias ibm5020
so i continues vi /etc/fstab and mount /newApps - > everything ok