add swap file on the linux-install
Tags: learning, linux, tutorial
Published: 2023-12-12 17:29:20


well from time to time i install a new notebook and doing so i want to add swap file on the linux-install.


So here a little story: well my notebook (a old one) doesn’t have that much  swap space  and yes i really think the swap space is not adequate and much enough,

so i think i have to do something and to create swap file on my Linux notebook. a friend of mine told me  that i can do even more - i can create multiple swap files as well he said.

well - it **allways helps me if i write down such steps **- so i can make sure if i have all steps together. And perhaps - if one tiny step is missing, feel free t add some lines - add a comment. Thank you in advance.

So here we **start**: this is the beginning

well i am trying to make up my mind how to  create swap file on  my Linux notebook. I am using a Ubuntu OS - so i guess that i have to test it on my ubuntu-notebook.

well i think that there are several preliminary steps do take - before i can set up a swap-file. the very very first step  in the show:

we just** make a new swap file**

At the beginning i think that i ll have to create a file with the size of swap space Well let’s assume that I want to add 2 GB of swap space to my Notebook - and to the operating system.

I will go through the necessary steps - that means all the steps that are necessary to do a nicer and good little Swap-space-file.

So First things first: we do some preliminariy things: 

at the very very beginning i think that i will have to use the  so called **fallocate command** to create a file of size 2 GB. This is the  command i have to add in the terminal:

`sudo fallocate -l 2G /swapfile`

well my girlfriend allways uses some of these commands when she is making a swapfile: the  recommends me  to allow only root to read and write to the swap file. So - to follow this recommendation (of my girlfriend) as she allways has good recommendations and i think it is a good thing i guess. We ll even see warning like “insecure permissions 0644, 0600 suggested” when we try to use this file for our new swap area (that we want to cr eate)


`sudo chmod 600 /swapfile`



Well to be frank  We have to go further: what about the  name of our tiny swap file!? **btw:** as mentioned above - yes it could be anything. If one needs more than one - if one needs 
multiple swap spaces, he can give it any appropriate name

like so for example.
`
swapspace_file_a, swapsüace_file_b etc. 
swapspace_file_c and so on and so forth `


Well we see here:_ It’s just a file with a so called predefined size: that is pretty easy. And yes - i follow to the recommendation of my girlfriend. 

That said we can go further in the story. 

the next step is pretty important: 

the filecreation-step  2: now we mark the new file as a so called swap space

Well at this point we  need to tell the Linux system that our new file - (which w e have created now) that  file will be used as a so called swap space:  we  can do that with mkswap tool.

`sudo mkswap /swapfile`

Well at this point we should be able to see an output like this:

`Setting up swapspace version 1, size = 2048 MiB 
and here we can do like so: use no label, UUID=xyz`


and now - we can go ahead and do even more. We can do more in the step5

Step 3:  the next step in the show: at this point we can do the good thing - and enable the swap file

With this step - our system knows that the file swapfile can be used as a so called swap space.  And this is generally a good thing!

but wait:  it is not done yet. We have to do even some steps more: that said - we ll  need to enable the swap file so that our system can start using this file as swap. And believe me dear  friend: this is a pretty important step We can not do the creation of the swap file without these preliminaries:

So the command here would be like the following command:

`sudo swapon /swapfile`

Now if we check the swap space, we should see that our Linux system recognizes and uses it as the swap area:

`swapon --show
NAME       TYPE   SIZE USED PRIO
/swapfile  file 2048M   0B   -2`


so we ll have to take care that the changes are pretty permanent on the system - that is on my tiny notebook; so in the next step i ll have to take care for this. We move ahead in the next step the Step 4 we do even more: now we make the changes permanent.  And my girlfriend said to me that this is damned important. So i belive this. 


This step seems to be important for me - since i thin that doing it will stop me form doing the same thing over and over - again and again: Well whatever we have done a swap-file-creation it is (first of all) is temporary file.

But - sure thing: we want more - at least i want to have  so i think that we have to reboot the system and all the changes will disappear. And yes: this is not what we want.

We want to make the changes permanent by adding the newly created swap `file to /etc/fstab file.`

That said - i think that i t is allways a good thing if we do a (quick and dirty) backup before we make any changes to the /etc/fstab file.

`sudo cp /etc/fstab bla bla bla bla  /etc/fstab.back`


Now we have came thus far - i am happy - and my girlfriend is happy too: 

Now we can add the following line to the end of /etc/fstab file:

`/swapfile none swap sw 0 0`


Woooh - wooh - we came thus far. 
Now it is necessary t o do a little step

`
echo '/swapfile none swap sw 0 0'` |


and thus it is important to see that 

` sudo tee -a /etc/fstab
`
Now after all these many many i guess that we have everything in place. our swap file will be used even after we reboot the notebook. We have come thus fare - thats awesome: in the last step we have to adjust the so called swappiness


well the so called swappiness parameters determines how often the swap space should be used. My girlfriend says - it is this a pretty important thing.  Well the so called swappiness value can be in the ranges from 0 (that is zero) to 120. Higher value means the swap space will be used even more often -that means even more frequently.

The default swappiness in Ubuntu desktop is about 50 : i guess while in server it is 1. 

well - we can check the swappiness with the following command:

`cat /proc/sys/vm/swappiness`