How do I Increase the Swap Size?

Question

I just recently increased my RAM, so I wanted to increase the swap size too. I know Elementary OS is based off Ubuntu, so I've been following Ubuntu information since there isn't much documentation for this stuff for Elementary OS specifically. I have 8GBs of ram now, and from what I understand, Ubuntu recommends that you allocate 11GBs of ram if you're planning on using hibernation, or 3GBs if you're not using hibernation. Is this true for Elementary OS too?

https://itsfoss.com/swap-size/

Anyways, I was following the following guide to increase the swap size:

https://linuxhandbook.com/increase-swap-ubuntu/

But when I got to the part where we use the follocate command to increase the swap file size, I get the following error:

fallocate: fallocate failed: Invalid argument

I figured I'd allocate 11GBs of space just to be safe, so I was using the following command:

sudo fallocate -l 11G /dev/dm-2

Any ideas as to what I'm doing wrong here? Is 11GBs a good size for the swap for Elementary OS with 8GBs of RAM? Am I getting GiB mixed up with GB in the follocate command?

Thanks in advance.

Answer 1

Generally a swap file would not be written in /dev, which contains device APIs, but in the root (/) directory. So long as you don’t mind having a file there, you can do something like this:

sudo fallocate -l 12G /swapfile

^{Note: The 12G size is different from what you specified not because 11GB is “wrong”, but because I generally leave 4GB of swap for buffers on machines that need to hibernate. Feel free to set any value you are comfortable with.}

From here it would be a good idea to verify the file exists and is the right size with:

ls -lh /swapfile

You should see a single file of the same size you specified in the fallocate command.

The next step is to enable the swap file. This is done by setting the permissions:

sudo chmod 600 /swapfile

Then marking the file as being for swapping purposes:

sudo mkswap /swapfile

If everything goes properly, you’ll see something like:

Setting up swapspace version 1, size = 12288 MiB (12884901888 bytes)
no label, UUID=6ecf2854-2ab9-4437-1ee0-577e740897ff

Now you can tell the system to use that space:

sudo swapon /swapfile

You can verify Elementary OS is using the swap file with the swapon command:

sudo swapon --show

You should see something like this:

NAME      TYPE   SIZE USED PRIO
/swapfile file 12288M   0B   -2

Finally, to make your swap file operational at boot time, you need to edit your fstab (File System Table) file:

sudo vi /etc/fstab

^{Note: Feel free to use any text editor you are familiar with. It does not need to be vi.}

Add this to the end of the file:

/swapfile     none     swap    sw   0   0

While this looks like a lot of steps, it’s not too bad when you step through the process to see what’s going on 👍🏻