In this post we will see how we can add a file as swap space in Linux. Same steps are to be followed for Redhat and Ubuntu Linux.
Type the following command to create 100MB swap file (1024 * 100MB = 102400 block size):
dd if=/dev/zero of=/swap1 bs=1024 count=102400
Secure swap file
Setup correct file permission for security reasons, enter:
# sudo chown root:root /swap1 # sudo chmod 0600 /swap1
Set up a Linux swap area
Type the following command to set up a Linux swap area in a file:
# sudo mkswap /swap1
Activate /swap1 swap space :
# sudo swapon /swap1
Update /etc/fstab file to make it persistent across reboot.
Add the following line in file:
/swap1 swap swap defaults 0 0
To check if the swap file is added or not
Type the following swapon command:
#sudo swapon -s Filename Type Size Used Priority /dev/dm-0 partition 839676 0 -1 /swap1 file 102396 0 -2
It should show you the new file.
If you want add a logical volume for swap please refer how to add LV for swap .