How to Add Swap Space on Ubuntu 18.04 and Above

Written by BiRU Thursday, 17 November 2022 06:42

Attention: open in a new window. PDFPrintE-mail

Check Swap Information

Command to check swap size.

swapon --show

Output:

NAME      TYPE      SIZE USED PRIO
/dev/vda2 partition 512M   0B   -2

Or you can check using free command.

free -m

Output:

              total        used        free      shared  buff/cache   available
Mem:            981         130         326           0         524         707
Swap:           511           0         511

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

Add Swap to your VPS

Command to create a Swap file.

NOTE: We are adding 1GB if you want to add 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

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

chmod 600 /swapfile

Set up a swap area on the file.

mkswap /swapfile

Output:

Setting up swapspace version 1, size = 1024 MiB (1073737728 bytes)
no label, UUID=3f6fee94-ed65-4187-8c67-05afcd0c8ef1

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@vps:~# swapon --show
NAME      TYPE       SIZE USED PRIO
/dev/vda2 partition  512M   1M   -2
/swapfile file      1024M   0B   -3
root@vps:~# free -m
              total        used        free      shared  buff/cache   available
Mem:            981         126          65           0         789         706
Swap:          1535           1        1534

NOTE: Now the added swap space can be seen.

Remove Swap File

Deactivate the swap space.

swapoff -v /swapfile

Output:

root@vps:~# 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.