# SQL replicas

GLPI can be configured to use replica databases in some cases to improve performance.

This tab is only visible if the option has been enabled in the [system tab](/documentation/modules/configuration/general/system.md).

![View SQL Replication](/files/C9Zv7faAboYdF9D2gyGi)

To activate the replica management, you just have to fill in the connection parameters. It is advisable to use a login that has only read privileges on the database.

You can use several replicates by separating them with a **blank space**. As the result in the config\_db\_slave.php file, the `dbhost` parameter will be an array.

A specific port can also be added.

{% hint style="warning" %}
If you use multiple replicas, the settings will apply to them all.
{% endhint %}

The SQL replicas will be used in at least the following cases:

* The main server cannot be reached. In this case, GLPI will switch to read-only mode.
* Running reports to reduce the load on the main server.

It is also possible to use replicas for the search engine depending on the option chosen.

* **Never**
* **If synced (all changes)** GLPI will check the synchronization and use the replica if all changes have been replicated.
* **If synced (current user changes)** GLPI will check the synchronization and use the replica if all the changes for the current user have been replicated. If using a read-only account, the replica will always be used.
* **If synced or read-only account** GLPI will check the synchronization and use the replica if all changes have been replicated. If using a read-only account, the replica will always be used.
* **Always**

{% hint style="danger" %}
When **always** using the replica, it is possible that the results will be **out of date**. A different option should be considered before this one.
{% endhint %}

{% hint style="info" %}
The replication configuration of your database is not set by GLPI. You still need to configure that with the appropriate tools for your database management system.
{% endhint %}


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