How to add a swap partition on Redhat Linux system?

I was trying to add a SWAP partition on a Linux system just like Solaris but didn't work. Then after some debugging, I found that method of adding swap in Linux requires few extra steps as mentioned below:

1. Create a partition (/dev/vdb4 in my case) using either fdisk or parted
2. Modify the parition type of this one to Hex code 82
3. Then Make sure the partition table of the disk is saved.
4. Once above is done, then run following commands as shown below:

[root@client1 ~]# free -m
             total       used       free     shared    buffers     cached
Mem:           996        264        732          0         19        118
-/+ buffers/cache:        125        871
Swap:            0          0          0

[root@client1 ~]# blkid -c /dev/null
/dev/vda1: UUID="ebf8bf59-fd61-45fd-93f8-c55214f2948f" TYPE="ext4"
/dev/vda2: UUID="ud5dLg-RYz6-WNMO-fj4W-5Z1e-KiHP-jGIk4r" TYPE="LVM2_member"
/dev/vdb1: UUID="37846ba4-2434-4cdc-b322-b7aa28854bfc" TYPE="ext2"
/dev/vdb2: UUID="162b6c2d-9ace-47b2-a7ba-b14abdf95bf4" TYPE="ext3"
/dev/vdb3: UUID="88e9c86d-d7ab-47cc-9746-3eec78e698e0" TYPE="ext4"
/dev/mapper/vg_client1-lv_root: UUID="5bf41004-9bd6-45ea-8880-eb0472fd134a" TYPE="ext4"
/dev/mapper/vg_client1-lv_swap: UUID="3fd6f62f-3538-4e1a-85a3-231771121cad" TYPE="swap"

[root@client1 ~]# which mkswap
/sbin/mkswap

[root@client1 ~]# mkswap -help
Usage: mkswap [-c] [-pPAGESZ] [-L label] [-U UUID] /dev/name [blocks]

[root@client1 ~]# mkswap /dev/vdb4
Setting up swapspace version 1, size = 352796 KiB
no label, UUID=da1f8f91-45c7-4bef-a47c-c5d1a0a4d081

[root@client1 ~]# blkid -c /dev/null
/dev/vda1: UUID="ebf8bf59-fd61-45fd-93f8-c55214f2948f" TYPE="ext4"
/dev/vda2: UUID="ud5dLg-RYz6-WNMO-fj4W-5Z1e-KiHP-jGIk4r" TYPE="LVM2_member"
/dev/vdb1: UUID="37846ba4-2434-4cdc-b322-b7aa28854bfc" TYPE="ext2"
/dev/vdb2: UUID="162b6c2d-9ace-47b2-a7ba-b14abdf95bf4" TYPE="ext3"
/dev/vdb3: UUID="88e9c86d-d7ab-47cc-9746-3eec78e698e0" TYPE="ext4"
/dev/vdb4: UUID="da1f8f91-45c7-4bef-a47c-c5d1a0a4d081" TYPE="swap"
/dev/mapper/vg_client1-lv_root: UUID="5bf41004-9bd6-45ea-8880-eb0472fd134a" TYPE="ext4"
/dev/mapper/vg_client1-lv_swap: UUID="3fd6f62f-3538-4e1a-85a3-231771121cad" TYPE="swap"

[root@client1 ~]# swapon -s
Filename                                Type            Size    Used    Priority

[root@client1 ~]# swapon -a

[root@client1 ~]# swapon -s
Filename                                Type            Size    Used    Priority
/dev/vdb4                               partition       352792  0       -1

[root@client1 ~]# free -m
             total       used       free     shared    buffers     cached
Mem:           996        264        732          0         20        118
-/+ buffers/cache:        125        871
Swap:          344          0        344

Lastly, dont forget to make an entry of this newly created swap partition in /etc/fstab file (so that it remains in effect even after reboot).

[root@client1 ~]# vi /etc/fstab
:
:
/dev/vdb4               swap                    swap    defaults        0 0
:
: