How to Add Swap Space on Ubuntu 23.04

Check Swap Information

Command to check swap size.

swapon --show

Output:

root@ubuntu:~# swapon --show
NAME      TYPE SIZE USED PRIO
/swap.img file 2.9G   0B   -2

Or you can check using the free command.

free -m

Output:

root@ubuntu:~# free -m
               total        used        free      shared  buff/cache   available
Mem:            2956         342        2501           1         268        2613
Swap:           2955           0        2955

NOTE: If the output is empty, it means that swap space is not enabled yet on your system.

Add Swap

Command to create a Swap file.

NOTE: We are adding 1GB if you want to add a different size then you can replace it in place of 1G

fallocate -l 1G /swapfile

or

dd if=/dev/zero of=/swapfile bs=1024 count=1048576

To set write permission.[Default permissions only enable for root user]

chmod 600 /swapfile

To set up a swap area on the file.

mkswap /swapfile

Output:

root@ubuntu:~# mkswap /swapfile
Setting up swapspace version 1, size = 1024 MiB (1073737728 bytes)
no label, UUID=f4baeeaf-a397-4b17-a378-452162110189

To activate the swap file.

swapon /swapfile

Open the following file and add the given content to change it to permanent.

nano /etc/fstab

Add the following line.

/swapfile swap swap defaults 0 0

Now check the swap size.

swapon --show

or

free -m

Output:

root@ubuntu:~# swapon --show
NAME      TYPE  SIZE USED PRIO
/swap.img file  2.9G   0B   -2
/swapfile file 1024M   0B   -3

root@ubuntu:~# free -m
               total        used        free      shared  buff/cache   available
Mem:            2956         369         976           1        1784        2586
Swap:           3979           0        3979

NOTE: Now the added swap space can be seen.

Remove Swap

Deactivate the swap space.

swapoff -v /swapfile

Output:

root@ubuntu:~# swapoff -v /swapfile
swapoff /swapfile

Next, remove the following line from the file /etc/fstab

/swapfile swap swap defaults 0 0

Command to remove the file.

rm /swapfile

This concludes our topic of configuring swap in ubuntu.