Linux divides its physical RAM (random access memory) into chucks of memory called pages. Swapping is the process whereby a page of memory is copied to the pre-configured space on the hard disk, called swap space, to free up that page of memory. The combined sizes of the physical memory and the swap space is the amount of virtual memory available.
The following is what you can do to add new swap space to your system:
To list swap partitions and swap files use:
Follow the steps to configure swap space:
Create swap files
cd /var/tmp dd if=/dev/zero of=swapfile1 bs=1024 count=1048576
This will create the file
/var/tmp/swapfile1 of size 1 GB. Using ‘dd’ command ensures that files have no holes.
Create swap area from swap files
/sbin/mkswap -c -v1 /var/tmp/swapfile1
This checks swapfile for bad blocks, then turns it into swap space
Enable swap files for swapping
Verify that system is using the new swap file
You should see the new entries for swap files.
Adding swap to fstab for automatic loading
Add the following line to the end of your
/var/tmp/swapfile1 swap swap defaults 0 0
That should add your swapfile automatically on every reboot.