How to create a swap file?07.12.13

when you need more swap space or when you forgot to create swap partiton on the installation you can make a additional swap file after.

Swapping to files is usually slower than swapping to a raw partition, so this is not the recommended permanent swapping technique.  Creating a swap file, however, can be a quick fix if you temporarily need more swap space. You can have up to 8 swap files, each with size of up to 16 MB. Here are the steps for making a swap file:
- Create a file with the size of your swap file:
dd if=/dev/zero of=/swapfile bs=1024 count=8192
This physically creates the swap file /swapfile, the block size is 1024 bytes, the file contains 8192 blocks, the total size is about 8 MB. [The dd command copies files. In the example above, the input file (if) was /dev/zero, the output file (of) was /swapfile . You cannot use the cp (copy) command for creating a swap file because the swap file must be physically continuous on the hard drive.]
- Set up the file with the command:
mkswap /swapfile 8192
- Force writing the buffer cache to disk by issuing the command:
sync
- Enable the swap with the command:
swapon /swapfile
When you are done using the swap file, you can turn it off and remove:
swapoff /swapfile
rm /swapfile
You may also want to see the nice info written by Linus Torvalds himself:
man mkswap

http://www.linuxhotbox.com/adminguide/lnag_drives.html

Anonymous