NAME

       radrelay -- Deprecated command.

DESCRIPTION

       The  functions  of  radrelay have been added to radiusd.  One benefit is that one instance of radiusd can
       read multiple detail files, among others.

       The rlm_sql_log module does something similar, but for SQL queries.  See it's man page for details.

REPLICATION FOR BACKUPS

       Many sites run multiple radius servers; at least one primary and one backup server. When the primary goes
       down, most NASes detect that and switch to the backup server.

       That will cause your accounting packets to go to the backup server - and some  NASes  don't  even  switch
       back to the primary server when it comes back up.

       The  result  is  that  accounting records are missed, and/or the administrator must jump through hoops in
       order to combine the different detail files from  multiple  servers.  It  also  means  that  the  session
       database ("radutmp", used for radwho and simultaneous use detection) gets out of sync.

       We  solve  this issue by "relaying" packets from one server to another, so they both have the same set of
       accounting data.

       See raddb/sites-available/buffered-sql for more information.

BUFFERING FOR HIGH-LOAD SERVERS

       If the RADIUS server suddenly receives a many accounting packets, there may be insufficient CPU power  to
       process  them  all in a timely manner.  This problem is especially noticeable when the accounting packets
       are going to a back-end database.

       Similarly, you may have one database that tracks "live" sessions,  and  another  that  tracks  historical
       accounting  data.   In  that  case,  accessing the first database is fast, as it is small.  Accessing the
       second database many be slower, as it may contain multiple gigabytes of data.  In  addition,  writing  to
       the first database in a timely manner is important, while data may be written to the second database with
       a few minutes delay, without any harm being done.

       See raddb/sites-available/copy-to-home-server for more information.

SEE ALSO

       radiusd(8), rlm_sql_log(5)

AUTHOR

       The FreeRADIUS Server Project

                                                 23 October 2007                                     RADRELAY(8)