Create a SWAP Partition having Size 512 MB in Linux

(1) free -m  used to check the free physical memory and SWAP Space

[root@CLIENT ~]# free -m
             total       used       free     shared    buffers     cached
Mem:           502        496          6          0         24        279
-/+ buffers/cache:        192        310
Swap:         1027          0       1027

(2) In this system partition SWAP  already exist  . so we extend the SWAP 

[root@CLIENT ~]# fdisk /dev/sda

The number of cylinders for this disk is set to 2714.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): n
First cylinder (2082-2714, default 2082):
Using default value 2082
Last cylinder or +size or +sizeM or +sizeK (2082-2714, default 2714): +512M

Command (m for help): t
Partition number (1-10): 10
Hex code (type L to list codes): l

 0  Empty           1e  Hidden W95 FAT1 80  Old Minix       bf  Solaris       
 1  FAT12           24  NEC DOS         81  Minix / old Lin c1  DRDOS/sec (FAT-
 2  XENIX root      39  Plan 9          82  Linux swap / So c4  DRDOS/sec (FAT-
 3  XENIX usr       3c  PartitionMagic  83  Linux           c6  DRDOS/sec (FAT-
 4  FAT16 <32M      40  Venix 80286     84  OS/2 hidden C:  c7  Syrinx        
 5  Extended        41  PPC PReP Boot   85  Linux extended  da  Non-FS data   
 6  FAT16           42  SFS             86  NTFS volume set db  CP/M / CTOS / .
 7  HPFS/NTFS       4d  QNX4.x          87  NTFS volume set de  Dell Utility  
 8  AIX             4e  QNX4.x 2nd part 88  Linux plaintext df  BootIt        
 9  AIX bootable    4f  QNX4.x 3rd part 8e  Linux LVM       e1  DOS access    
 a  OS/2 Boot Manag 50  OnTrack DM      93  Amoeba          e3  DOS R/O       
 b  W95 FAT32       51  OnTrack DM6 Aux 94  Amoeba BBT      e4  SpeedStor     
 c  W95 FAT32 (LBA) 52  CP/M            9f  BSD/OS          eb  BeOS fs       
 e  W95 FAT16 (LBA) 53  OnTrack DM6 Aux a0  IBM Thinkpad hi ee  EFI GPT       
 f  W95 Ext'd (LBA) 54  OnTrackDM6      a5  FreeBSD         ef  EFI (FAT-12/16/
10  OPUS            55  EZ-Drive        a6  OpenBSD         f0  Linux/PA-RISC b
11  Hidden FAT12    56  Golden Bow      a7  NeXTSTEP        f1  SpeedStor     
12  Compaq diagnost 5c  Priam Edisk     a8  Darwin UFS      f4  SpeedStor     
14  Hidden FAT16 <3 61  SpeedStor       a9  NetBSD          f2  DOS secondary 
16  Hidden FAT16    63  GNU HURD or Sys ab  Darwin boot     fb  VMware VMFS   
17  Hidden HPFS/NTF 64  Novell Netware  b7  BSDI fs         fc  VMware VMKCORE
18  AST SmartSleep  65  Novell Netware  b8  BSDI swap       fd  Linux raid auto
1b  Hidden W95 FAT3 70  DiskSecure Mult bb  Boot Wizard hid fe  LANstep       
1c  Hidden W95 FAT3 75  PC/IX           be  Solaris boot    ff  BBT           
Hex code (type L to list codes): 82
Changed system type of partition 10 to 82 (Linux swap / Solaris)

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.


(3) Reboot the system after this


[root@CLIENT ~]# reboot




(4) Now activate the SWAP partition


[root@CLIENT ~]# mkswap /dev/sda10
Setting up swapspace version 1, size = 518156 kB
[root@CLIENT ~]# swapon /dev/sda10

(5) NOW again check the SWAP Space the size of SWAP is increased by 512 MB

[root@CLIENT ~]# free -m
             total       used       free     shared    buffers     cached
Mem:           502        495          7          0         23        284
-/+ buffers/cache:        186        316
Swap:         1521          0       1521


(6) Open the file /etc/fstab and enter the following entry as in the image

[root@CLIENT ~]# vim /etc/fstab