How to create Linux's swap swap partition file method steps

Swap profile

In Linux, Swap (i.e., swap partition), similar to Windows's virtual memory, is when the memory is not enough, 1 part of the hard disk space virtual memory use, so as to solve the problem of insufficient memory capacity.

How do I create an Swap file

1. Create 1 file to swap

sudo fallocate -l 1G /swapfile

If faillocate is not installed or you receive an error message, fallocate failed: Operation not supported can create an interchange file using the following command:

sudo dd if=/dev/zero of=/swapfile bs=1024 count=1048576

2. Set the right permissions

Only root users can write and read swap files. Set the correct permissions type:

sudo chmod 600 /swapfile

3. Set up the Linux swap area

Use the mkswap utility to set the file to the Linux swap area:

sudo mkswap /swapfile

4. Enable switching

Activate the interchange file using the following command:

sudo swapon /swapfile

To make the change permanently open the /etc/fstab file and attach the following lines:

/swapfile swap swap defaults 0 0

5. Verify the switching status

To verify that the exchange is active, we can use the swapon or free commands as follows:

sudo swapon --show

The output

NAME   TYPE SIZE  USED PRIO
/swapfile file 1024M 507.4M  -1

sudo free -h

The output

       total    used    free   shared buff/cache  available
Mem:      488M    158M     83M    2.3M    246M    217M
Swap:     1.0G    506M    517M

How to adjust swappiness

Swappiness is an Linux kernel attribute that defines how often the system uses swap space. Swappiness can have values between 0 and 100. A lower value will enable the kernel to avoid swapping as much as possible, while a higher value will enable the kernel to use swap space more actively.

The default swappiness value is 60. You can check the current swappiness value by typing the following command:

sudo dd if=/dev/zero of=/swapfile bs=1024 count=1048576

0

The output

[

60

]

While the desktop can use the swappiness value of 60, you may need to set a lower value for the production server.

For example, to set the swappiness value to 10, type:

sudo dd if=/dev/zero of=/swapfile bs=1024 count=1048576

1

To keep this parameter unchanged after reboot, append the following lines to the /etc/ sysctl.conf file:

sudo dd if=/dev/zero of=/swapfile bs=1024 count=1048576

2

The optimal swappiness value depends on your system workload and how memory is used. You should adjust this parameter in small increments to find the best value.

How do I delete the swap file

If you want to deactivate and delete the swap file for any reason, follow these steps:

1. First, deactivate the exchange using the following command:

sudo swapoff -v /swapfile

2. Delete swap file entry /swapfile swap swap defaults 0 0 from /etc/fstab file.

3. Finally, delete the actual swapfile file:

sudo dd if=/dev/zero of=/swapfile bs=1024 count=1048576

4