Swap is space on a disk that is reserved to be used as virtual memory. A swap partition is not present on Cloud Servers by default, but swap can be added to a server by allocating a swap file.

We have discussed previously in 2 posts to create a SWAP space in Linux, this post describes create swap another method is,

Swap space method 1
Swap space method 2

You can add 1GB of swap to your server, fallocate command is really helpful.

$ sudo fallocate -l 1G /swapfile 

If fallocate fails or is not installed this command, try swap space creation from the link,

Give read permission with below command,

$ sudo  chmod 600 /swapfile 

Format the file for swap.

$ sudo  mkswap /swapfile 

Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=4d49c74c-4bfa-43ae-bff8-633f616e6ef0

Add the file to the system as a swap file.

$ sudo swapon /swapfile

Include the swapfile line to the end of /etc/fstab to make the change permanent.

$ sudo vim /etc/fstab 

/swapfile none swap sw 0 0 

Check that the swap file was created.

$ sudo swapon -s

Now, you can check the RAM space using free command,
$ free -m

             total       used       free     shared    buffers     cached
Mem:          3764        877       2887          1        160        204
-/+ buffers/cache:        512       3251
Swap:         1023          0       1023