Create New File System To New Partition No such file or directory

I create the New Partition under /dev/sda sata Hard disk(dev/sda3). After create the the partition using fdisk then while I create the file system using mkfs.ext3 command I got the following error message.
[root@node2 ~]# mkfs.ext3 /dev/sda3
mke2fs 1.39 (29-May-2006)
Could not stat /dev/sda3 --- No such file or directory
The device apparently does not exist; did you specify it correctly?
I try to mount with the following command
[root@node1 ~]# mount -t ext3 /dev/sda3 /mnt
mount: wrong fs type, bad option, bad superblock on /dev/sda3,
missing codepage or other error
(aren't you trying to mount an extended partition,
instead of some logical partition inside?)
In some cases useful info is found in syslog - try
dmesg | tail or so

PROBLEM

Linux Operating System It does not find the New Partition from the Hard Disk.
SOLUTIONActually From the resource they suggest me to restart the Operating System But, It will take time,
We can Avoid To restart the Server using
#partprobe using these command we can Update the partition Table.
So Linux Kernel it can find the New Partition.
Then we can create the file system with out reboot the system.
HereAfter Using mkfs command we can create the file system.
[root@node1 /]# partprobe
[root@node1 /]# mkfs.ext3 /dev/sdb2
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
36519936 inodes, 73021449 blocks
3651072 blocks (5.00%) reserved for the super user
...............  
ERROR MESSAGE
#mount /dev/sdb2 /mnt
After Mounting check using #df -T check whethere file system is created perfectly or Not.
#df -T
Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/sdb1 ext3 36904824 7261744 27738176 1% /mnt
[root@node2 ~]# mkfs.ext3 /dev/sda3
mke2fs 1.39 (29-May-2006)
Could not stat /dev/sda3 --- No such file or directory
The device apparently does not exist; did you specify it correctly?
I try to mount with the following command
[root@node1 ~]# mount -t ext3 /dev/sda3 /mnt
mount: wrong fs type, bad option, bad superblock on /dev/sda3,
missing codepage or other error
(aren't you trying to mount an extended partition,
instead of some logical partition inside?)
In some cases useful info is found in syslog - try
dmesg | tail or so