Bug 241528

Summary: syslog-ng 2.0.4: Number of allowed concurrent connections exceeded; num='10', max='10'
Product: [Fedora] Fedora Reporter: Nicolas Mailhot <nicolas.mailhot>
Component: syslog-ngAssignee: Jose Pedro Oliveira <jose.p.oliveira.oss>
Status: CLOSED RAWHIDE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: pvrabec
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Hardware: All   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2007-06-20 13:10:03 EDT Type: ---
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Bug Blocks: 235704    

Description Nicolas Mailhot 2007-05-27 06:09:58 EDT
Description of problem:

I get lots of "Number of allowed concurrent connections exceeded; num='10',
max='10'" in /var/log/messages so maybe syslog-ng defaults as shipped by fedora
are too small (this is a single-user home system)

Version-Release number of selected component (if applicable):

Comment 1 Nicolas Mailhot 2007-05-31 12:56:27 EDT
Experimenting shows the default 10 is too small to handle all the logs spilled
at system statup and unix-stream("/dev/log"); needs to be changed in 
unix-stream("/dev/log" max-connections(48)); (32 is too small, I blame 48 on ATM)
Comment 2 Jose Pedro Oliveira 2007-05-31 14:20:45 EDT
The new max-connections enforcement introduced in syslog-ng 2.0.4 is 
quite "nasty" (the 10 connections default is in fact too low).

With the default configuration I didn't detect any warning but as soon I
started using yum to update/install packages I started seeing the
"Number of allowed concurrent connections exceeded" message.

Bumping the max-connections to 20 solved the problem (with the default

     source s_sys {
         file ("/proc/kmsg" log_prefix("kernel: "));
    -    unix-stream ("/dev/log");
    +    unix-stream ("/dev/log" max-connections(20));

I will try to update syslog-ng in my main log server to version 2.0.4
and see the result.

From the syslog-ng-2.0.4 NEWS file
        Mon, 14 May 2007 11:47:48 +0200

        * This version of syslog-ng fixes a bug in enforcing the
          max-connections() limit for various stream-like sources
          (unix-stream and tcp). Previously this limit was not enforced,
          thus production environments may use an inadequate value.
          Validate your max-connection() settings before upgrading
          and check your logs for rejected connections.

Comment 3 Nicolas Mailhot 2007-05-31 14:47:04 EDT
IMHO for the default local system source it's better to be too big than too
small, and 32 was still too small on my system (without too many log-spilling
daemons installed)
Comment 4 Jose Pedro Oliveira 2007-06-10 10:58:39 EDT
syslog-ng 2.04 is now available in F-7 updates-testing.

The default configuration file now defines the number of max-connections for
unix-streams as 32.

   unix-stream ("/dev/log" max-connections(32));