It is always a good idea to back up your data so that you have a safe copy of it while installing a new ActiveReports Server version or in the event of a disaster.
In order to backup and restore data, you can use corresponding import/export REST API. It allows import and export of all or particular set of resources.
You can also use Migration PowerShell Module sample shipped with ActiveReports Server (C:\ActiveReports 12 Server\SDK\Samples) to create backup and recover data.

To back up and recover your data using Migration PowerShell Module sample

1. Run the sample. See Migration PowerShell Module Sample topic for the detailed steps.
2. Export all the contents of the C:\ActiveReports 12 Server\Data folder to a zip folder by running the following PowerShell script:
   Export-ArsData -Path C:\...\Documents\backup.zip
   The backup is created.
   
3. Install a fresh instance of ActiveReports Server.
4. Import the contents in C:\ActiveReports 12 Server\Data folder of the new installed version by running the following PowerShell script:
   Import-ArsData -Path C:\...\Documents\backup.zip
   The data saved in backup.zip folder is recovered.