mosquitto.db home assistant where stored

Daniel Parker

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28-02-2025

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Home Assistant's MQTT integration relies on the Mosquitto MQTT broker for message handling. Many users wonder where the crucial mosquitto.db file, containing persistent session information, is stored. This comprehensive guide will clarify its location across different Home Assistant installations. Understanding this is key to managing your MQTT configuration and data.

Understanding Mosquitto.db

mosquitto.db is a crucial SQLite database file used by the Mosquitto MQTT broker. It stores persistent session information, including subscribed topics and client details. This means even if your Home Assistant instance restarts, the broker retains the connection and subscription information from previously connected clients. Knowing where it's stored is essential for backing up your MQTT configuration, troubleshooting connection issues, and performing maintenance.

Locating Mosquitto.db in Different Home Assistant Setups

The location of mosquitto.db significantly depends on how you've installed and configured Home Assistant. Let's break it down:

1. Home Assistant Supervised/OS Installations (Most Common)

For most users employing the supervised or operating system (OS) installations of Home Assistant (e.g., using the official Home Assistant OS, Docker, or Virtual Machine), mosquitto.db is usually located within the Home Assistant Supervisor's data directory. The precise path might vary slightly depending on your OS, but generally follows this structure:

• Linux (Common): /data/mosquitto/
• Windows: %APPDATA%\Home Assistant\mosquitto\

Important Note: The /data directory often points to a symbolic link, particularly on Home Assistant OS. The actual location of your data might be on an external drive or partition. Check your Home Assistant configuration to confirm.

2. Home Assistant Containerized Installations (Docker)

If you use Docker to run Home Assistant, the mosquitto.db location is determined by your Docker volume mapping. You'll need to check your docker-compose.yml file (or equivalent) to see where the /data directory is mapped to on your host machine. It typically points to a directory you've created specifically for Home Assistant data persistence.

Example docker-compose.yml (illustrative):

version: "3.9"
services:
  homeassistant:
    image: homeassistant/home-assistant
    volumes:
      - /path/to/your/homeassistant/data:/data

In this example, /path/to/your/homeassistant/data/mosquitto/ would be where mosquitto.db is stored.

3. Home Assistant on a Raspberry Pi (using Raspbian/other Linux distributions)

The principles are similar to the Linux instructions above. The path /data/mosquitto/ is a frequent location, but always verify your Home Assistant installation's data directory.

Backing Up mosquitto.db

Regular backups of mosquitto.db are highly recommended. This ensures that your MQTT broker's session data is preserved in the event of system failure, Home Assistant corruption, or accidental deletion. You can simply copy the mosquitto.db file to a safe location.

Troubleshooting Connection Issues

If you experience MQTT connection problems, examining the mosquitto.db file (with appropriate caution – avoid modifying it directly) can offer clues. It may contain information about failed connections or other issues.

Conclusion

The location of mosquitto.db within your Home Assistant setup depends greatly on your installation method. By understanding these variations and the importance of this file, you can effectively manage your MQTT configuration and ensure data persistence. Remember to back up your mosquitto.db regularly to protect your configuration.