freeradius load and message handling

[Alan DeKok]

On Jun 14, 2016, at 4:00 PM, liran kessel <lirankessel at gmail.com> wrote:
> we have a freeradius server collecting accounting events from a few Nokia GGSN’s and are storing them into the MySQL DB.
> 
> Now that we have activated all messages we are receiving around 20K messages a minute, and have started seeing these events in the radius.log
> 
> Tue Jun 14 22:53:33 2016 : Info: WARNING: Please check the configuration file. 	The value for 'max_requests' is probably set too low.
> 
> it was originally set to 1024, when we increased it and set it to 4096 the amount of such events was reduced but still didn’t disappear. 
> If we set it higher (6100 for  example) we start getting these errors
> 
> Tue Jun 14 21:30:02 2016 : Error: Received conflicting packet from client localhost port 41935 - ID: 200 due to unfinished request 192178.  Giving up on old request.
> 
> why does this event appear? what would be the best way to manage this situation?

  It appears because your database is overloaded.  It can't write the records quickly enough.

> The server has 8 Cores and 4GB of RAM. 
> It seems that the CPU isn’t overly loaded, but our RAM is almost completely used by the Radius and Mysql processes.
> 
> Will adding RAM to this server help us?  or isn’t it the bottleneck for this issue?

  The bottleneck is the database.  Typically it's waiting on "sync to disk".  And there's very little you can do about that.

  Alan DeKok.