1RADRELAY(8)                    FreeRADIUS Daemon                   RADRELAY(8)
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NAME

6       radrelay -- Deprecated command.
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DESCRIPTION

9       The  functions  of radrelay have been added to radiusd.  One benefit is
10       that one instance of radiusd can read multiple detail files, among oth‐
11       ers.
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13       The  rlm_sql_log  module  does  something similar, but for SQL queries.
14       See it's man page for details.
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REPLICATION FOR BACKUPS

17       Many sites run multiple radius servers; at least one  primary  and  one
18       backup  server.  When the primary goes down, most NASes detect that and
19       switch to the backup server.
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21       That will cause your accounting packets to go the the backup  server  -
22       and  some  NASes  don't  even switch back to the primary server when it
23       comes back up.
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25       The result is that accounting records are missed, and/or  the  adminis‐
26       trator must jump through hoops in order to combine the different detail
27       files from multiple servers. It also means that  the  session  database
28       ("radutmp", used for radwho and simultaneous use detection) gets out of
29       sync.
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31       We solve this issue by "relaying" packets from one server  to  another,
32       so they both have the same set of accounting data.
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34       See raddb/sites-available/buffered-sql for more information.
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BUFFERING FOR HIGH-LOAD SERVERS

37       If the RADIUS server suddenly receives a many accounting packets, there
38       may be insufficient CPU power to process them all in a  timely  manner.
39       This  problem  is  especially noticable when the accounting packets are
40       going to a back-end database.
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42       Similarly, you may have one database that tracks "live"  sessions,  and
43       another  that tracks historical accounting data.  In that case, access‐
44       ing the first database is fast, as it is small.  Accessing  the  second
45       database  many be slower, as it may contain multiple gigabytes of data.
46       In addition, writing to the first database in a timely manner is impor‐
47       tant,  while data may be written to the second database with a few min‐
48       utes delay, without any harm being done.
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50       See raddb/sites-available/copy-to-home-server for more information.
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SEE ALSO

53       radiusd(8), rlm_sql_log(5)
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AUTHOR

56       The FreeRADIUS Server Project
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60                                23 October 2007                    RADRELAY(8)