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-ng	Assignee:	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:	rawhide	CC:	pvrabec
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2007-06-20 17:10:03 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	235704

Description Nicolas Mailhot 2007-05-27 10:09:58 UTC

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):

syslog-ng-2.0.4-2.fc8

Comment 1 Nicolas Mailhot 2007-05-31 16:56:27 UTC

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 18:20:45 UTC

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
configuration).

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

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
----------------------------------
2.0.4
        Mon, 14 May 2007 11:47:48 +0200

        IMPORTANT NOTES:
        * 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 18:47:04 UTC

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 14:58:39 UTC

syslog-ng 2.04 is now available in F-7 updates-testing.

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

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