---
locale: "en"
updated_at: "2025-10-30T09:39:21.824Z"
canonical: "https://www.isdecisions.com/en/userlock/docs/reference/server-settings/synchronization"
---

# Synchronization

Sync settings and maintenance action for backup server.

> **Note**
>
> - To access this page, go to **Server settings ▸ Synchronization** on a UserLock backup server.
> - You need at least *read* [permission](/userlock/docs/reference/server-settings/permissions) on Server settings to view this page.

## Overview

The Synchronization page is available only on a UserLock server configured with the **Backup role**. Its purpose is to ensure that if the Primary server becomes unavailable, the Backup server can instantly take over session monitoring and policy enforcement without disruption.

Synchronization keeps both servers aligned by replicating configuration and session data. It works in two complementary ways:

- **Event synchronization**: copies UserLock settings and updates the session database based on the Primary server’s audited events.
- **Session synchronization**: mirrors the live session list as displayed on the Primary server.

Together, these mechanisms make sure the Backup server is always ready to replace the Primary if needed.

> **Note**
>
> - To learn more about what a Backup server is and how it works, see [Backup server (Core concept)](/userlock/docs/reference/core-concepts/servers-types#backup-server).
> - Adding a Backup server to your UserLock infrastructure is **strongly recommended**.

## Synchronization settings

![](https://a.storyblok.com/f/122374/1363x696/3a863902d6/server-settings-synchronization-settings.png)

Synchronization can be enabled or disabled at any time. By default, it runs automatically every minute.

You can adjust this **synchronization period** to control the balance between performance and continuity:

- **short intervals** keep the Backup server closely aligned with the Primary server’s state,
- **longer intervals** reduce server load but increase the risk of outdated data in case of failover.

## Maintenance actions

![](https://a.storyblok.com/f/122374/1363x369/059d6449b2/server-settings-synchronization-maintenance.png)

From this section, administrators can:

- **Force an event synchronization** to immediately replicate all configuration and audited event data,
- **Force a session synchronization** to refresh the active sessions list,
- **Test the connection** between Primary and Backup to make sure communication is working properly.

These tools are particularly useful after configuration changes, or when verifying the Backup server’s readiness.

## Logging and troubleshooting

If a synchronization fails, UserLock writes an entry in the [Windows Application event log](/userlock/docs/troubleshooting/common-issues#synchronization-issues).

This allows administrators to track issues, integrate with monitoring tools, and ensure that any problem is detected early.