>>can we make more often backup?
You can manually trigger a backup of your configuration under Setup >> System Administration >> Administrative Tools >> Create Configuration Snapshot or via the following API call:
<your Core Server>/api/savenow.htm?username=<admin username>&passhash=<admin passhash>
>>How much resources PRTG takes to make this backup?
This is hard to answer as it very much depends on the available hardware resources and the actual size of your PRTG instance.
>>Can you provide a link to article about this part?
Please refer to our backup and restore guides.
Sven Roggenhofer [Paessler Technical Support]