Normally the swap space partitioned twice of RAM space, for example if your system RAM space is 2048 MB swap space 1024*4 = 4096 MB or minimum swap memory partitioned
equal of RAM memory.
Check the RAM Memory total, used and free space by using free command,
-m specified that MB size as human read,
# free -m
total used free shared buffers cached
Mem: 2006 1820 185 0 53 764
-/+ buffers/cache: 1002 1004
Swap: 1012 14 998
In my system 2GB RAM space but the Swap space is 1GB only, so I will increase Swap space upto 2GB.
The size of the swap file calculate in MB size and multiple by 1024 to determine the block size for 2GB 2048*1024=2097152. On the shell prompt can calculate the total count using “bc” command,
# bc
bc 1.06.95
Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.
2048*1024
2097152
quit
The below command count being equal to the block size,
# dd if=/dev/zero of=/swapfile bs=1024 count=2097152
2097152+0 records in
2097152+0 records out
2147483648 bytes (2.1 GB) copied, 87.1816 s, 24.1 MB/s
Make swap file using below command,
# mkswap /swapfile
Setting up swapspace version 1, size = 2054140 KiB
no label, UUID=cc79c13d-ab21-4a64-89a6-54b4718184c1
To enable swap space
# swapon /swapfile
Now, check the memory space,
# free -m
total used free shared buffers cached
Mem: 2006 1820 185 0 53 764
-/+ buffers/cache: 1002 1004
Swap: 3060 14 3046
This is temporarily mapped the memory space, if you want to swap file available even after the reboot add the below line in the file system /etc/fstab
# vim /etc/fstab
/swapfile swap swap defaults 0 0
:wq!
To find out swap area usage summary by device,
# swapon -s
or
# cat /proc/swaps
Comments (0)