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)