Two radius servers and active sessions

[Marcin Romanowski]

Hello,

I'm going to set up two freeradius servers, one as primary second as slave.
Both devices in different location.
I'm going to genrate plain files for configuration for PPPoE servers.
My problem is how to properlly sychronize actual active sessions for using
simultanieusly = 1.

What is proper way to acheve that solution?

Best regards