Steps to create swap file on Centos Server

[Neha]

Can you please guide me through the steps to create swap file on Centos Server?

[Mandeep]

Hi Neha,

Here, I'll consider that you need to create a Swap space of 4 GB as as a reference and you may follow below steps to do so.

Connect to the server as root user.

1. Check total disk space available on the server

df -h

2. Manipulate File space. Create a swapfile in the location where it can't be deleted. I've considered /root location for the same.

fallocate -l 4G /root/4GB.swap

3. Use following command, the count parameter will be used to allocate the desired block size 4 GB.

dd if=/dev/zero of=/root/4GB.swap bs=1024 count=4048576

4. Create a swap file.

mkswap /root/4GB.swap

5. Change the permission to 600.

chmod 600 /root/4GB.swap

6. To enable Swap immediately and not on boot time.

swapon /root/4GB.swap

7. To enable swap at boot time add an entry to /etc/fstab file

vi /etc/fstab

/root/4GB.swap  swap  swap  defaults 0  0

8. To check the mount or entry is correct.

mount -a

9. Swap is now available and can be checked using below command.

free -m

[Administrator]

Thanks great information on how to create swap space.

[Mandeep]

You're welcome !!