# How to Manage a Swap Partition in Linux

> URL: https://www.atlantic.net/vps-hosting/how-to-manage-a-swap-partition-in-linux/ | Published: 2021-05-19 | Updated: 2023-11-18 | Author: Hitesh Jethva

Swap is a physical space on the disk that is used when the system RAM is full. When the memory usage in a system exceeds the available RAM, the kernel will move the idle page to the swap memory. Swap space can be created on a separate partition or a swap file. If your server is running on a VPS and a swap partition is not present, then you will need to create a swap file.

In this post, we will show how to create and manage a swap space on Linux.

## Step 1 – Verify Swap Partition

Before starting, you will need to check whether Swap is enabled or not in your system.

You can check it with the following command:

```
swapon --show
```

If the output is empty that means there is not any swap space active in your system.

## Step 2 – Create a Swap File

As you can see, there is not any swap space active in your system. So you will need to create a new swap file to your system.

First, create a swap file with size 4GB using the following command:

```
dd if=/dev/zero of=/swapfile bs=4096 count=1048576
```

You should see the following output:

```
1048576+0 records in
1048576+0 records out
4294967296 bytes (4.3 GB, 4.0 GiB) copied, 9.47796 s, 453 MB/s
```

Next, set the correct permission on swapfile with the following command:

```
chmod 600 /swapfile
```

Next, create a swap area on the swapfile with the following command:

```
mkswap /swapfile
```

Output:

```
Setting up swapspace version 1, size = 4 GiB (4294963200 bytes)
no label, UUID=035ada64-2c1a-407d-9f1a-c0dd02b8dcd4
```

Next, activate the swap space using the following command:

```
swapon /swapfile
```

The above command will activate the swap space temporarily.

To set up it permanently, edit the /etc/fstab file:

```
nano /etc/fstab
```

Add the following line:

```
/swapfile swap swap defaults 0 0
```

```
Save and close the file then verify the swap partition with the following command:
```

```
swapon --show
```

You should see the following output:

```
NAME      TYPE SIZE USED PRIO
/swapfile file   4G   0B   -2
```

## Step 3 – Check Swap Usage

To check the Swap usage information, run the following command:

```
free -m
```

You should see the following output:

```
              total        used        free      shared  buff/cache   available
Mem:           1987          74          69           0        1843        1745
Swap:          4095           0        4095
```

You can also check it with the following command:

```
cat /proc/swaps
```

You should see the following output:

```
Filename                                Type            Size    Used    Priority
/swapfile                               file            4194300 0       -2
```

You can also use the top command to check the swap usage in real-time:

```
top
```

You should see the following output:

```
Tasks:  84 total,   1 running,  83 sleeping,   0 stopped,   0 zombie
%Cpu(s):  5.9 us,  5.9 sy,  0.0 ni, 88.2 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
MiB Mem :   1987.7 total,     68.0 free,     74.8 used,   1844.9 buff/cache
MiB Swap:   4096.0 total,   4096.0 free,      0.0 used.   1745.5 avail Mem
```

You can also use the vmstat command to check the swap usage:

```
vmstat 2 6
```

You should see the following output:

```
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 3  0      0  69356  12096 1877228    0    0    35   652   31   59  0  0 99  0  0
 0  0      0  69420  12096 1877228    0    0     0     0   24   42  0  0 100  0  0
 0  0      0  69388  12096 1877228    0    0     0     0   22   40  0  0 100  0  0
```

## Step 4 – Remove a Swap Space

In order to remove the swap space, you will need to deactivate the swap space first. You can do it with the following command:

```
swapoff -v /swapfile
```

Next, edit the /etc/fstab file and remove the following line:

```
nano /etc/fstab
```

Remove the following line:

```
/swapfile swap swap defaults 0 0
```

Next, remove the swap file using the following command:

```
rm -rf /swapfile
```

Next, verify whether the swap space is removed or not with the following command:

```
swapon --show
```

## Conclusion

In the above guide, you learned how to check and create a swap space on Linux. You also learned how to monitor the swap space with different commands. Get started today with your [VPS](https://www.atlantic.net/vps-hosting/) from Atlantic.Net.