NTA Flow Storage database maintenance
Maintaining the NTA Flow Storage database requires setting a retention period that corresponds with the amount of data you need to keep and the free disk space available on your NTA Flow Storage database disk.
Retention Period specifies the time for which flow data are stored in the database until they expire and are permanently deleted.
To optimize the retention period for your NTA Flow Storage database, collect data for a few days. You should then have an idea of the volume of data your network produces with NetFlow enabled. Consider the space taken up by the database, and then adjust the retention period accordingly.