error discarding packet

Borislav Dimitrov b.dimitrov at ngsystems.net
Wed Dec 23 14:43:18 CET 2009 

In radiusd.conf:

# THREAD POOL CONFIGURATION
thread pool {
	start_servers = 1
	max_servers = 1
	min_spare_servers = 1
	max_spare_servers = 1
	max_requests_per_server = 0
}

...but instead of ones (1s) put something more appropriate for your  
network usage (like 5s or 7s). It's similar to Apache's thread pool  
settings... Stay monitoring and tuning until the error discarding  
duplicate packet disappears or becomes very rare. Also look at the  
Acct-Delay-Time parameter returned from the NAS to FR. It should be 0.  
If it's more than 0, then there's some delay. When you increase you  
thread pool settings the CPU usage will start increasing as FR starts  
processing more requests simultaneously/concurrently. Also check your  
NAS documentation for configuration options of these timeout etc  
parameters. For Cisco they are like that:
> "radius-server retransmit 0" etc

С поздрави

Борислав Димитров
e-mail: b.dimitrov at ngsystems.net
GSM: 0888 51 55 45; 0889 28 54 57
NG Systems
Лавеле 32, ет: 4,
София, България




On 23.12.2009, at 15:36, Alisson wrote:

> hi, my DB is ok I tested with another programms e etc, and is  
> running well
>
> how I set the thread pool to better concurrency?
>
> 2009/12/23 Borislav Dimitrov <b.dimitrov at ngsystems.net>
> Hi,
>
> This question has been answered many times on this ML. I myself have  
> (at least tried) answered it two times. Here're some of my previous  
> messages:
>
> Msg1:
> Hi,
>
> I've already tried to answer a similar question some time ago (and  
> I'm probably not the only one) but anyways...
> The cause of the problems probably is some delay or packet loss or  
> something like that. Notice the Acct-Delay-Time value increasing as  
> the NAS retries to send the "lost" accounting packet (although - at  
> least in my case - it wasn't lost but just its processing was  
> delayed). I've experienced such issues with Cisco VoIP routers - the  
> router's log is flooded with RADIUS Server DEAD - and then ... ALIVE  
> messages and in the FR log you can see the retries with the values  
> of Acct-Delay-Time increasing. The main cause of the problem may be  
> different, so you'll have to check it in your case. In my case it  
> was caused by the thread pool settings not being appropriate for the  
> load. In this case the CPU usage stays low but it's not used because  
> you cannot achieve good concurrency and request have to await each  
> other to finish. So find the main cause for your problems and  
> eliminate it. The other thing is that most NASs have options to  
> configure the RADIUS timeout, dead, retransmit etc times. E.g.for  
> Cisco you could try "radius-server retransmit 0".
>
> Msg2:
> Hi,
>
> As far as I can see, the people on the list have provided you with a  
> lot of very useful suggestions on what could cause the problem. As I  
> said earlier (let me clarify) and to help you narrow things a little  
> bit - it's probably due to the RADIUS response timing out hence the  
> NAS complains the server is dead and later when it responds finally  
> it marks it as alive again. The reasons can be different depending  
> on your setup - slow network, database, custom module (like rlm_perl/ 
> python etc) or as I suggested (from my personal experiences)  
> improperly configured concurrence settings of FR itself. See which  
> component of your setup is causing the slow responds (it can be the  
> backend, or messed up FR configuration) and fix it. Just for  
> completeness check your NASs manuals - most have these settings  
> configurable - response timeouts, retransmits, marking the server as  
> dead etc but playing with the NAS while possibly useful is probably  
> not the main issue in your setup - check what is slowing things down.
>
> Msg3:
> Hi there,
>
> I may be mistaken but... these are log message on the NAS aren't they?
> If this is the case, I've experienced similar behavior with Cisco  
> VoIP routers (RADIUS Server DEAD and then... ALIVE). This happens if  
> you haven't properly enabled concurrency in FreeRADIUS - the CPU  
> usage stays low 0%-1%-2% but if the requests are many they are  
> obviously waiting each other... This happens when you have stared  
> FreeRADIUS with the -X key (I think it starts with a single thread  
> then) or have too low values for the thread pool parameters (and/or  
> the *_clones options of rlm_perl which are to be deprecated soon).  
> If you configure proper values according to the expected usage  
> (concurrent requests), then the request won't wait each other to  
> finish while the CPU stays unused and you'll avoid this annoying  
> message in your logs. A sure sing that something like that is going  
> on is the Acct-Delay-Time parameter with values greater than 0 -  
> that is for accounting not sure for auth etc. Anyways if the values  
> of that parameter are high (they are in seconds I think) then the  
> requests are waiting too long and hence the error messages.
>
> Bottom line:
> 1) Check the ML for more info
> 2) The NAS can be configured when to timeout and resend the RADIUS  
> packages
> 3) Something is slowing down your setup. It may be the DB or  
> something else. If your CPU usage stays low (< 5%), check your  
> thread pool settings and increase them to achieve better concurrency.
>
> Sincerely,
>
> Borislav Dimitrov
> e-mail: b.dimitrov at ngsystems.net
> GSM: 0888 51 55 45; 0889 28 54 57
> NG Systems
> Lavele 32 str, fl: 4,
> Sofia, Bulgaria
>
>
>
>
> On 23.12.2009, at 15:10, Alisson wrote:
>
> hi, in another day I posted this same error ' Error: Discarding  
> duplicate request from client '
>
> and the answer was 'your database is slow'
>
> so I upgrade my server with more memory, and changed servers  
> variables...
>
> but, i'm still having this problem
>
> and I dont know what can be
>
> -- 
> Att.
> Alisson F. Gonçalves
> Sistemas de Informação - UFGD
> -
> List info/subscribe/unsubscribe? See http://www.freeradius.org/list/users.html
>
>
> -
> List info/subscribe/unsubscribe? See http://www.freeradius.org/list/users.html
>
>
>
> -- 
> Att.
> Alisson F. Gonçalves
> Sistemas de Informação - UFGD
> -
> List info/subscribe/unsubscribe? See http://www.freeradius.org/list/users.html

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