[Updated July 26, 2020]: Change swapfile permission; Set swapfile in /etc/fstab.
Swap is a special area on your computer, which the operating system can use as additional RAM.
Starting with Ubuntu 17.04, the swap partition was replaced by a swap file. The main advantage of the swap file is easy resizing.
In the following example, we’ll extend the swap space available in the /swapfile from 4 GB to 8 GB.
-
- Turn off all swap processes
sudo swapoff -a
- Resize the swap
sudo dd if=/dev/zero of=/swapfile bs=1G count=8
if = input file
of = output file
bs = block size
count = multiplier of blocks - Change permission
sudo chmod 600 /swapfile
- Make the file usable as swap
sudo mkswap /swapfile
- Activate the swap file
sudo swapon /swapfile
- Edit /etc/fstab and add the new swapfile if it isn’t already there
/swapfile none swap sw 0 0
- Check the amount of swap available
grep SwapTotal /proc/meminfo
- Turn off all swap processes
Hi Bogdan
Thanks for this. I created the swapfile successfully with 20GB but I notice there are now two swapfiles – the 20GB one and the original one created by the OS (4GB). From the fstab file I can see two entries. The second on was entered by myself. Would this cause any issues? Thanks.
/dev/mapper/cryptswap none swap defaults 0 0
/swapfile none swap sw 0 0
When I run sudo swapon -s, it shows the /swapfile type as ‘file’ and the ‘/dev/dm-0’ type as ‘partition’.
Edwin
Hi Edwin,
From what I can see, the OS created an encrypted swap partition. This is most likely because you choose to encrypt your Ubuntu installation. In this case, you can use a partition tool such as GParted or Disks (from Gnome) to resize the swap partition.
I haven’t verified this, but I don’t think the swap file you created is being used if you also have the encrypted one.
Thank you. It simply and elegantly worked 😃
does this same process apply for swap partition?
Hi Meet,
Steps 1, 4, 5, 6 and 7 are also applicable to a swap partition.
You will need a partition editor program such as GParted to create the swap partition.
When adding the partition to fstab, you’ll need to add it by UUID (instead of just using “/swap”) which you can find out by running the “blkid” command.
Thank you for your clear explanation, I could resolve few issues in my OS by extending Swap memory.
Thank you, I’m glad to hear that.
yes the fstab works for persistent! thanks!
This tutorial is awesome! I finally updated my swap memory to 32Gb on Ubuntu 20.04 and now it match with my 16Gb RAM memory. Thanks for sharing this, very helpful
Thank you!
Glad I could help 🙂
Thanks for the clear commands , It’s working my machine!
In step 2, I got the following error:
DD: Memory Exhausted by Input Buffer of Size Bytes
This can be fixed by using this command instead:
sudo dd if=/dev/zero of=/swapfile bs=1M count=2000
(2000 = 2GB)
Hi Bogdan,
thanks for the post. The changes appear not to be persistent with a reboot. How can we make them persistent?
Thanks
Hi Enrique,
Can you please add this line at the end of the /etc/fstab file?
/swapfile none swap sw 0 0
Please let me know if this works for you and I’ll update the article.
Thank you,
Bogdan