Skip to main content

syslog-ng statistics

For a long time I meant to give the "log statistics" feature of syslog-ng an overhaul, and finally with the advent of syslog-ng 3.0, this was done.

I'm not sure all of you know, but even earlier syslog-ng versions (2.1 and 2.0) did collect some per-source and per-destination statistics. These were reported periodically in the system log. The problem with this approach that it didn't really scale: with a large configuration the statistics message could become kilobytes long, and parsing this information from a file possibly several gigabytes in size is daunting.

syslog-ng 3.0 has two important changes in this area: it adds several new kinds of counters (like per-host counters), and a UNIX domain socket where you can query the current status of these counters.

As counters certainly have an overhead, you can now control how much statistics you want to gather. The new stats_level() option has three levels for now:
  1. stats_level(0) is basically the same as earlier syslog-ng versions, per-source and per-destination statistics are kept here. This is the default.
  2. stats_level(1) adds new counters without a big overhead, that is it adds counters for TCP connections, but does not keep per-host counters
  3. stats_level(2) adds counters that can have a measurable performance impact, it adds for example per-host (as in $HOST) counters and also keeps track of the time the last message was received from a given host. These counters usually require an hash table lookup in the fastpath.
Once you have the counters, you can still use the venerable "log statistics" message, by setting the stats_freq() option which defaults to 10 minutes, just like in earlier versions.

However if you don't want to dig the logs produced by syslog-ng, you can also use the new UNIX domain socket at /var/run/syslog-ng/syslog-ng.ctl (the path might depend on the compilation options).

If you connect to this socket using netcat (some netcat versions do support UNIX domain sockets), and you send a "STATS" command to it, you get the list of counters.

There are no proper, command line clients for the UNIX domain channel yet, but if you have some scripting ability, you can start gather statistics easily, without the hassles of parsing log files, right after installing a syslog-ng 3.0 snapshot. :)
Labels:

Comments

Anonymous said…
Half of the sample log message is not visible - i guess it is not wrapped automatically.
9:53 AM
Post a Comment

Popular posts from this blog

syslog-ng fun with performance

I like christmas for a number of reasons: in addition to the traditional "meet and have fun with your family", eat lots of delicious food and so on, I like it because this is the season of the year when I have some time to do whatever I feel like. This year I felt like doing some syslog-ng performance analysis. After reading Ulrich Deppert's series about stuff "What every programmer should know about memory" on LWN, I thought I'm more than prepared to improve syslog-ng performance. Before going any further, I'd recommend this reading to any programmer, it's a bit long but every second reading it is worth it. As you need to measure performance in order to improve it, I wrote a tool called "loggen". This program generates messages messages at a user-specifyable rate. Apart from the git repository you can get this tool from the latest syslog-ng snapshots. Loggen supports TCP, UDP and UNIX domain sockets, so really almost everything can be me...
17 comments
Read more

syslog-ng OSE 2.1 released

I have just uploaded the first release in the syslog-ng Open Source Edition 2.1 branch to our website. It is currently only available in source format at this location: http://www.balabit.com/downloads/files/syslog-ng/sources/2.1/src This release synchronizes the core of syslog-ng to the latest PE version and adds the SQL destination driver. This is an alpha release and thus might be rough around the edges, but it basically only contains code already tested in the context of the Premium Edition. The SQL functionality requires a patched libdbi package, which is available at the same link. We're going to work on integrating all our libdbi related patches to the upstream package. If you want to know how the SQL logging works, please see the Administrator's Guide or our latest white paper Collecting syslog messages into an SQL database with syslog-ng. The latter describes the Premium Edition, but it applies to the Open Source one equally well.
6 comments
Read more

syslog-ng 3.2 changes

I've just pushed a round of updates to the syslog-ng 3.2 repository, featuring some interesting stuff, such as: SQL reorganization: Patrick Hemmer sent in a patch to implement explicit transaction support instead of the previous auto-commit mode used by syslog-ng. I threw in some fixes and refactored the code somewhat. Configuration parser changes: the syntax errors produced by syslog-ng became much more user-friendly: not only the column is displayed, but also the erroneous line is printed and the error location is also highlighted. Additional plugin modules were created: afsql for the SQL destination, and afstreams for Solaris STREAMS devices. Creating a new plugin from core code takes about 15 minutes. I'm quite satisfied. With the addition of these two modules, it is now possible to use syslog-ng without any kind of runtime dependency except libc. The already existing afsocket module (providing tcp/udp sources & destinations) is compiled twice: once with and once withou...
4 comments
Read more