NetFlow database stores the data needed for chart and alarms in NetFlow module. You can configure NetFlow database in 
> Settings > NetFlow Settings > Configuration with the following parameters:
- Maximum database size - oldest data will be removed first
- Minimum database size in weeks - the system will warn you before database space runs out
NetFlow Analyzer will warn you if your storage space is full and tell you exactly what actions are advised. Warnings are sent by email to NetVizura administrators and displayed when you log-in. Warning message is triggered when application concludes that Maximum database size will be reached without storing minimum amount of traffic in weeks (Minimum database size in weeks).
Example of storage warning message for Maximum database size set to 30 GB and Minimum database size in weeks set to 52 weeks:
9 weeks of data (5.5 GB) still needs to be stored, but only 5 more weeks' worth of space (3 GB) remain in the database storage.
You need to provide more space for NetFlow database (currently set to 30 GB), or lower the minimum number of weeks (currently set to 52 weeks) for which you would like to keep the data. 52 weeks is approximately 33 GB.
NetFlow database stores the data needed for chart and alarms in NetFlow module. When the database size increases beyond configured limit, oldest entries will be deleted although those entries would fall within configured minimum number of weeks - consequently charts and alarms corresponding to deleted entries would be missing.