Re: [Nufw-devel] DOS mode, packet logging

[Glen Ogilvie]

----- "Glen Ogilvie" <address@hidden> wrote:

> Hi,
> 
> I have noticed that on a couple of occasions problems with logging.
> I've seen messages like:
> 
> nuauth[14187]: [7] No packet logging to avoid logger DOS
> 
> appear in nuauth log.  After this message, logging to the database for
> authenticated users
> stops, and does not seem to start again until nuauth is restarted. 
> This breaks single sign on and traffic
> accounting.
> 
> It looks to me like nuauth is supposed to switch back from DOS mode
> when the g_thread_pool_unprocessed(nuauthdatas->user_loggers) <
> nuauthconf->max_unassigned_messages
> 
> called in: act_on_loggers_processing, which is called from the
> main_cleanup method in authsrv.c, which 
> appears to me to be called by nuauth_main_loop using a timer.
> 
> I am a little lost as to how the thread pool
> (nuauthdatas->user_loggers) empties itself.   Do the user_loggers
> thread have a timeout that will cause them to be destroyed or retry if
> they failed to log correctly, say for example that the DB was busy?
> 
> Any help around what I can do to:
> 1 - reduce the chance of packets not being logged
> 2 - get the system to come back out of DOS protection mode without a
> restart of nuauth would be appreciated.  
> 3 - if this is a bug, then a patch to fix it would be good.
> 
> The version I am looking at is: 2.2.21


Of further information to this, we are using the MySQL logging module,
compiled again mysql 5.0.67, and have mysql_request_timeout=5 in the
configuration file.  This seems to happen during high load, and when
the database is fairly busy.

I've been looking at the source code for the mysql module.
I see MYSQL_OPT_CONNECT_TIMEOUT is set,
but MYSQL_OPT_WRITE_TIMEOUT and MYSQL_OPT_READ_TIMEOUT are
not set. 

I don't know if this is related to my problem, but am wondering about it. See:
http://dev.mysql.com/doc/refman/5.1/en/mysql-options.html

Regards
Glen Ogilvie