To add a swap file:
- Determine the size of the new swap file in megabytes and multiply by 1024 to determine the number of blocks. For example, the block size of a 64 MB swap file is 65536.
- At a shell prompt as root, type the following command with count being equal to the desired block size:
dd if=/dev/zero of=/swapfile bs=1024 count=65536
- Change the persmissions of the newly created file:
chmod 0600 /swapfile
- Setup the swap file with the command:
mkswap /swapfile
- To enable the swap file immediately but not automatically at boot time:
swapon /swapfile
- To enable it at boot time, edit /etc/fstab to include the following entry:
/swapfile swap swap defaults 0 0
The next time the system boots, it enables the new swap file.
- After adding the new swap file and enabling it, verify it is enabled by viewing the output of the command cat /proc/swaps or free.