### Understand the alert

This alert monitors the state of your `systemd` swap units and is triggered when a swap unit is in the `failed` state. If you receive this alert, it means that you have an issue with one or more of your swap units managed by `systemd`.

### What is a swap unit?

A swap unit in Linux is a dedicated partition or a file on the filesystem (called a swap file) used for expanding system memory. When the physical memory (RAM) gets full, the Linux system swaps some of the least used memory pages to this swap space, allowing more applications to run without the need for extra physical memory.

### What does the failed state mean?

If a `systemd` swap unit is in the `failed` state, it means that there was an issue initializing or activating the swap space. This might be due to configuration issues, disk space limitations, or filesystem errors.

### Troubleshoot the alert

1. Check the status of the swap units:

   To list the swap units and their states, run the following command:

   ```
   systemctl list-units --type=swap
   ```

   Look for the failed swap units and note their names.

2. Investigate the failed swap units:

   For each failed swap unit, check its status and any relevant messages by running:

   ```
   systemctl status <swap_unit_name>
   ```

   Replace `<swap_unit_name>` with the name of the failed swap unit.

3. Check system logs:

   Examine the system logs for any errors or information related to the failed swap units with:

   ```
   journalctl -xeu <swap_unit_name>
   ```

4. Identify the issue and take corrective actions:

   Based on the information from the previous steps, you may need to:

   - Adjust swap unit configurations
   - Increase disk space or allocate a larger swap partition
   - Resolve disk or filesystem issues
   - Restart the swap units

5. Verify that the swap units are working:

   After resolving the issue, ensure the swap units are active and running by repeating step 1.

### Useful resources

1. [systemd.swap — Swap unit configuration](https://www.freedesktop.org/software/systemd/man/systemd.swap.html)
