synchronize accounting

[Marcin]

Hi, I'm testing freeradius 2.1 from debian stable.
I'd like to set two independent serwer with the same configuration but the
problem is with synchronize active sessions radutmp. I use simultaneous-use
= 1. So if first server is broken client won't be able to authorise :/

How can I achieve synchronized two servers with active sessions?
I don't want to using sql database to avoind problems with other servers,
daemons.

-- 
Pozdrawiam
Marcin / nicraM