Scylla University Live | July 28 & 29 Free Virtual Training Event
Learn More >

How to Set up a Swap Space

Note

It is recommended to run the scylla_setup script to setup your swap space. scylla_setup runs a script called scylla_swap_setup. You can also run the script using the Set Up Swap Space with a Script procedure below. If this doesn’t work use the procedure below to Set Up Swap Space with a File.

Set Up Swap Space with a Script

The help for the script can be accessed by scylla_swap_setup --help.

scylla_swap_setup --help
usage: scylla_swap_setup [-h] [--swap-directory SWAP_DIRECTORY] [--swap-size SWAP_SIZE]

Configure swap for Scylla.

optional arguments:
 -h, --help            show this help message and exit
 --swap-directory SWAP_DIRECTORY
   specify swapfile directory
 --swap-size SWAP_SIZE
   specify swapfile size in GB

Procedure

  1. Run the script setup command in a terminal specifying the target directory and size.

sudo scylla_swap_setup --swap-directory /tmp/swp --swap-size SWAP_SIZE 500

Set Up Swap Space with a File

Use this procedure if the Set Up Swap Space with a Script procedure did not give you the desired results.

This tutorial is suitable for any Linux distribution.

This procedure adds 6GB of swap to your server. If you want to add a different amount, replace 6G with the size you require.

Keep in mind that

swap size should be set to either total_mem/3 or 16GB - lower of the two.

total_mem is the total size of the nodes memory.

For example:

  • If the node total_mem is 18GB swap size should be set to 6GB.

  • If the node total_mem is 240GB swap size should be set to 16GB.

Procedure

  1. Create a file that will be used for swap.

    sudo fallocate -l 6G /swapfile
    
  2. Change the permissions setting on the file so that only the root user is be able to write and read the swap file.

    sudo chmod 600 /swapfile
    
  3. Run the Use mkswap utility to set up the file as Linux swap area.

    sudo mkswap /swapfile
    
  4. Enable the swap.

    sudo swapon /swapfile
    
  5. To make the change sustainable, open the /etc/fstab file and append the following:

    /swapfile swap swap defaults 0 0
    
  6. Verify that swap is active.

    sudo swapon --show
    NAME      TYPE  SIZE   USED PRIO
    /swapfile file 6024M 507.4M   -1
    

Remove a Swap File

  1. Deactivate Swap.

    sudo swapoff -v /swapfile
    
  2. Remove the sap file entry by editing the /etc/fstab file and removing /swapfile swap swap defaults 0 0.

  3. Delete the swap file.

    sudo rm /swapfile
    

Additional Information