SWAP Management - Create, Activate, Swappiness, Deactivate, Remove [EASY GUIDE]

CREATE

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1. Creating a Swap File

sudo dd if=/dev/zero of=/swapfile bs=1024 count=<1024*desired_swap-size_in_MB>

Keep block size bs=1024

1. Set the file permissions to 600 to prevent regular users to write and read the file:

sudo chmod 600 /swapfile

1. Create a Linux swap area on the file:

sudo mkswap /swapfile

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ACTIVATE

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1. Activate swap file

sudo swapon /swapfile

1. To Make the change permanent open the /etc/fstab file:

sudo nano /etc/fstab

1. Paste following line

/swapfile swap swap defaults 0 0 

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SWAPPINESS

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1. Check swappiness value

cat /proc/sys/vm/swappiness

On Ubuntu, the default swappiness value is set to 60

1. Modify swappiness

sudo sysctl vm.swappiness=10

While the swappiness value of 60 is OK for most Linux systems, for production servers, you may need to set a lower value.

1. Make swappiness permanent To make this parameter persistent across reboots, append the following line to the /etc/sysctl.conf file:

vm.swappiness=10

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DEACTIVATE

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1. Deactivate swap file

sudo swapoff -v /swapfile

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REMOVE

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1. Remove the swap file entry /swapfile swap swap defaults 0 0 from the /etc/fstab file. From Step 5.

2. Finally, remove the actual swapfile from your disk
   

sudo rm /swapfile

You can find your swapfile at root directory

To check the status of swap use free -h or swapon -s