persistRoutesDuration

The number of minutes a route server will wait after BGP is re-established to unpersist the routes in the FIB and RIB. Value must be in the range of 1-5. Required if PersistRoutes is enabled.

If you set the duration to 1 minute, then when your network appliance re-establishes BGP with route server, it has 1 minute to relearn it's adjacent network and advertise those routes to route server before route server resumes normal functionality. In most cases, 1 minute is probably sufficient. If, however, you have concerns that your BGP network may not be capable of fully re-establishing and re-learning everything in 1 minute, you can increase the duration up to 5 minutes.