The NSX Manager database is designed to store up to 20,00,000 flow records over a period of 15 days. In a large-scale environment, to avoid hitting the flow records limit, you can exclude specific flows from the exclusion settings, such as layer-2 flows, specific sources, specific destinations, or specific ports. To retain flow data records for longer than 15 days, you would need the flow to be exported to an external IPFIX collector.
From NSX 6.2, Flow Monitoring and IPFIX features are decoupled, so you can enable IPFIX independently of Flow Monitoring on NSX.
IPFIX or Internet Protocol Flow Information eXport is an IETF protocol that was created based on the need for a universal standard of export for internet protocol flow ...
