--- title: "Decisions Disaster Recovery Architecture" slug: "decisions-disaster-recovery-architecture" updated: 2025-07-17T23:43:08Z published: 2025-07-17T23:43:08Z --- > ## Documentation Index > Fetch the complete documentation index at: https://documentation.decisions.com/llms.txt > Use this file to discover all available pages before exploring further. # Decisions Disaster Recovery Architecture ## Overview A **Disaster Recovery (DR) Server** is a standby instance of the Decisions Server, configured in a separate data center or availability zone from the primary environment. It is designed to take over operations if a failure or disaster impacts the **primary server**. The **DR architecture** ensures business continuity by maintaining System uptime and safeguarding data through Always-On SQL replication, synchronized file systems, and mirrored configurations. The DR server remains offline during normal operations but is prepared to activate immediately during a failover scenario, using shared licensing, identical configuration files, and secure database connections to mirror the primary environment. --- ## Primary vs. Disaster Recovery Database Connections #### Primary Database Connection - The [**Primary Connection String**](https://documentation.decisions.com/v9/docs/setting-fail-over-connection-string#:~:text=Database%20Connection%20String) from the installation will be the **Database Connection** used for the main server. #### Disaster Recovery / Secondary Connection - The [**Secondary Connection String**](https://documentation.decisions.com/v9/docs/setting-fail-over-connection-string#:~:text=SecondaryDatabaseConnection%20String) operates as a **Failover****Connection**if the **Primary Connection String** fails. --- ## Configure Decisions as a Disaster Recovery server To configure Decisions as a **DR Server**, at least two Decisions Installations will be needed. One of the installations is kept offline but references an **MSSQL Database** with **Always-On Replication** set for the **Production Server**. The **Connection String** applied to the **Decisions Installer** needs to reference the replicated database in the Disaster Recovery Server. In addition, the **Keys.dat** and **databaseid.txt** files in the **DR Server File System** must be replaced with the same files from the **Production Environment File System** to operate identically in a **Disaster Event**. While the DR server is inactive, the settings.xml tag for this property should be set to true. This prevents other users (except administrators) from logging into the server. ![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/20210216-1030-03.png) DR Server location:It is recommended that the Disaster Recovery servers be located at a different data center / availability zone than the primary Decisions environment. --- ## Licensing Considerations for Disaster Recovery Servers When using Machine Key-based licensing, there are critical steps that must be followed to ensure the Disaster Recovery (DR) environment operates correctly during a failover: - Apply the License to the Production Database First: Machine-key based licenses are tied to specific machines and must be stored in the license_key table of the production database. To achieve this: 1. Point the DR server's database connection string to the live production database. 2. Run the license application process on the DR server to store its license in the production database. 3. After the license has been successfully applied, update the DR server to point back to the DR database. - License Application Process: - No need to reinstall Decisions. Run DecisionsServerInstaller.exe, select Edit Settings, change the DatabaseConnectString to the production database, and save. After applying the license, reverse the process to point back to the DR database. - Use either the Restart Service option in the Installer or run IISRESET to apply the changes. - Alternative Licensing Option: If preferred, self-licensing can be enabled, which allows the server to acquire and apply licenses automatically when needed. This must be supported and enabled explicitly. - Key Note: - The license_key table can store entries for multiple machines, allowing production and DR servers to operate independently after appropriately configuring licensing. - Failure to follow this process may result in the DR server being unable to activate during a disaster event due to missing or incorrect license records. - For DR server instances, ensure that the `databaseid.txt` and `keys.dat` files are copied into the instance-specific file storage directory on the DR server. --- ## Step-by-Step Setup 1. [**Install**](https://documentation.decisions.com/v9/docs/installation-ms-sql) Decisions on the Disaster Recovery Server on a new database; note that this database will need a name different from the one used for **Always-On Replication**. 2. **Stop**the **Decisions Server Service (or IIS App Pool)**. 3. **Run**the [**DecisionsServerInstaller.exe**](https://releases.decisions.com/Releases/) on the **Disaster Recovery Server** again and select **Edit Settings**. 4. Change the**Initial Catalog** field of the **Database Connection String** to match the name of the **Always-On Replication****Database**. 5. While modifying the **Settings**, make sure that **Offline** is set to **true**. 6. Copy the **Keys.dat** and **databaseid.txt** files from the production server **Decisions Services Manager** directory and use them to replace the keys.dat and databaseid.txt files in the **Disaster Recovery Server File System**. #### Additional Notes If the Decisions Server being backed up is a [**Multi-Tenant**](https://documentation.decisions.com/v9/docs/about-multi-tenancy) environment, navigate to the **DR Server** **Settings.xml** file and set the **** property to **false**. The **databaseid.txt** file needs to be identical on the **Production**and **Disaster Recovery Server** as [**Scheduled Jobs**](https://documentation.decisions.com/v9/docs/understanding-scheduled-jobs) operate differently if the file differs from the one present at the time of their creation, even if the database being used is identical. --- ## Syncing Data To Disaster Recovery Server | **Files Backup** | For a complete and comprehensive list of the recommended files to **Backup**from the Decisions environment, please visit our [Decisions & File System Backup](https://documentation.decisions.com/v9/docs/backup-of-decisions-database-and-file-system) article. | | --- | --- | | **Settings.xml File** | The configurations in the [**Settings.xml**](https://documentation.decisions.com/v9/docs/system-settings-overview-settings-xml) file between the **Primary Server** and **Disaster Recovery Server** must match, except **true**. | | **File Storage** | The files in file storage are saved as regular files. This will require the organization's IT team to determine the best method of file replication in the **Disaster Recovery** environment. | | **Other Files** | **Keys.dat**, **Modules**files, **Databaseid.txt**. | --- For further information on Installation, visit the [Decisions Forum](https://community.decisions.com/categories/InstallationSetup).