How to Add Swap Space on Debian 12

This guide is applicable only for KVM based VPSes and dedicated servers, If you wish to increase swap on your OpenVZ based VPS please contact us via a Support ticket from the client area.

Check Swap Information

Command to check swap size.

swapon --show

Output:

root@vps:~# swapon --show
NAME      TYPE      SIZE USED PRIO
/dev/vda1 partition 487M   0B   -2

Or you can check using free command.

free -m

Output:

root@vps:~# free -m
               total        used        free      shared  buff/cache   available
Mem:            1967         303         918           0         898        1663
Swap:            486           0         486

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 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

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

chmod 600 /swapfile

Set up a swap area on the file.

mkswap /swapfile

Output:

root@vps:~# mkswap /swapfile
Setting up swapspace version 1, size = 1024 MiB (1073737728 bytes)
no label, UUID=d8dd15f9-036e-40e5-946f-83bb5e1341a3

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/vda1 partition  487M   0B   -2
/swapfile file      1024M   0B   -3
root@vps:~# free -m
               total        used        free      shared  buff/cache   available
Mem:            1967         307         913           0         900        1659
Swap:           1510           0        1510

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 Debian.


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