Statistics reference

Statistics are a legacy way to access the status of AxoSyslog. Metrics are newer and in active development. Many metrics aren’t available as legacy statistics.

You can list all active statistics on your AxoSyslog host using the following command (this lists the statistics, without their current values): syslog-ng-ctl query list "*"

Format of statistics

To list the statistics and their values, use the following command: syslog-ng-ctl query get "*"

Example output:

destination.java.d_elastic#0.java_dst(ElasticSearch,elasticsearch-syslog-ng-test,t7cde889529c034aea9ec_micek).stats.dropped=0
destination.java.d_elastic#0.java_dst(ElasticSearch,elasticsearch-syslog-ng-test,t7cde889529c034aea9ec_micek).stats.processed=0
destination.java.d_elastic#0.java_dst(ElasticSearch,elasticsearch-syslog-ng-test,t7cde889529c034aea9ec_micek).stats.queued=0
destination.d_elastic.stats.processed=0

The displayed statistics have the following structure.

• The type of the object (for example, dst.file, tag, src.facility)

• The ID of the object used in the syslog-ng.conf configuration file, for example, d_internal or source.src_tcp. The #0 part means that this is the first destination in the destination group.

• The instance ID (destination) of the object, for example, the filename of a file destination, or the name of the application for a program source or destination.

• The status of the object. One of the following:

  • a: active. At the time of querying the statistics, the source or the destination was still alive (it continuously received statistical data).

  • d: dynamic. Such objects may not be continuously available, for example, like statistics based on the sender’s hostname. These counters only appear above a certain value of stats(level()) global option:

    • host: source host, from stats(level(2))
    • program: program, from stats(level(3))
    • sender: sender host, from stats(level(3))

    The following example contains 6 different dynamic values: a sender, a host, and four different programs.

    src.sender;;localhost;d;processed;4
    src.sender;;localhost;d;stamp;1509121934
    src.program;;P-18069;d;processed;1
    src.program;;P-18069;d;stamp;1509121933
    src.program;;P-21491;d;processed;1
    src.program;;P-21491;d;stamp;1509121934
    src.program;;P-9774;d;processed;1
    src.program;;P-9774;d;stamp;1509121919
    src.program;;P-14737;d;processed;1
    src.program;;P-14737;d;stamp;1509121931
    src.host;;localhost;d;processed;4
    src.host;;localhost;d;stamp;1509121934
    

    To avoid performance issues or even overloading AxoSyslog, you might want to limit the number of registered dynamic counters in the message statistics. To do this, configure the stats(max-dynamics()) global option.

  • o: This object was once active, but stopped receiving messages. (For example, a dynamic object may disappear and become orphan.)

  Note The AxoSyslog application stores the statistics of the objects when AxoSyslog is reloaded. However, if the configuration of AxoSyslog changed since the last reload, the statistics of orphaned objects are deleted.

The connections statistics counter displays the number of connections tracked by AxoSyslog for the selected source driver.

Example configuration and statistics output

The following configuration will display the following syslog-ng-ctl statistics output:

Configuration:

source s_network { 
  tcp( 
    port(8001)  
  ); 
};

Statistics output:

src.tcp;s_network#0;tcp,127.0.0.5;a;processed;1
src.tcp;s_network#0;tcp,127.0.0.1;a;processed;3
src.tcp;s_network;afsocket_sd.(stream,AF_INET(0.0.0.0:8001));a;connections;2

Statistics reference

The type of the statistics:

• batch_size_avg: When batching is enabled, then this shows the current average batch size of the given source or destination.

• batch_size_max: When batching is enabled, the value of batch_size_max shows the current largest batch size of the given source or destination.

• discarded: The number of messages discarded by the given parser. These are messages that the parser could not parsed, and are therefore not processed. For example:

  parser;demo_parser;;a;discarded;20
  

• dropped: The number of dropped messages. AxoSyslog could not send these messages to the destination and the output buffer got full, so messages were dropped by the destination driver, or AxoSyslog dropped the message for some other reason (for example, a parsing error).

• eps_last_1h: The EPS value of the past 1 hour.

• eps_last_24h: The EPS value of the past 24 hours.

• eps_since_start: The EPS value since the current AxoSyslog start.

  Note

  When using the eps_last_1h, the eps_last_24h, and the eps_since_start statistics, consider the following:

  • EPS stands for “event per second”, and in our case, a message received or sent counts as a single event.
  • The eps_last_1h, the eps_last_24h, and the eps_since_start values are only approximate values.
  • The eps_last_1h, the eps_last_24h, and the eps_since_start values are automatically updated every 60 seconds.

• matched: The number of messages that are accepted by a given filter. Available for filters and similar objects (for example, a conditional rewrite rule). For example, if a filter matches a specific hostname, then the matched counter contains the number of messages that reached the filter from this hosts.

  filter;demo_filter;;a;matched;28
  

• memory_usage: The memory used by the messages in the different queue types (in bytes). This includes every queue used by the object, including memory buffers (log-fifo) and disk-based buffers (both reliable and non-reliable). For example:

  dst.network;d_net#0;tcp,127.0.0.1:9999;a;memory_usage;0
  

  Note The memory usage (size) of queues is not equal to the memory usage (size) of the log messages in AxoSyslog. A log message can be in multiple queues, thus its size is added to multiple queue sizes. To check the size of all log messages, use global.msg_allocated_bytes.value metric.

• msg_size_max: The current largest message size of the given source or destination.

• msg_size_avg: The current average message size of the given source or destination.

  Note

  When using the msg_size_avg and msg_size_max statistics, consider that message sizes are calculated as follows:

  • on the source side: the length of the incoming raw message
  • on the destination side: the length of the outgoing formatted message

• not_matched: The number of messages that are filtered out by a given filter. Available for filters and similar objects (for example, a conditional rewrite rule). For example, if a filter matches a specific hostname, then the not_matched counter contains the number of messages that reached the filter from other hosts, and so the filter discarded them.

  Note

  Since the not_matched metric applies to filters, and filters are expected to discard messages that do not match the filter condition, not_matched messages are not included in the dropped metric of other objects.

  filter;demo_filter;;a;not_matched;0
  

• processed: The number of messages that successfully reached their destination driver.

  Note Consider that a message that has successfully reached its destination driver does not necessarily mean that the destination driver successfully delivered the messages as well. For example, a message can be written to disk or sent to a remote server after reaching the destination driver.

• queued: The number of messages passed to the message queue of the destination driver, waiting to be sent to the destination.

• stamp: The UNIX timestamp of the last message sent to the destination.

• suppressed: The number of suppressed messages (if the suppress() feature is enabled).

• written: The number of messages successfully delivered to the destination. This value is calculated from other counters: written = processed - queued - dropped. That is, the number of messages AxoSyslog passed to the destination driver (processed) minus the number of messages that are still in the output queue of the destination driver (queued) and the number of messages dropped because of an error (dropped, for example, because AxoSyslog could not deliver the message to the destination and exceeded the number of retries).

This metric is calculated from other metrics. You cannot reset this metric directly: to reset it, you have to reset the metrics it is calculated from.

Availability of statistics

Certain statistics are available only if the stats(level()) global option is set to a higher value.

• Level 0 collects only statistics about the sources and destinations.
• Level 1 contains details about the different connections and log files, but has a slight memory overhead.
• Level 2 contains detailed statistics based on the hostname.
• Level 3 contains detailed statistics based on various message parameters like facility, severity, or tags.

When receiving messages with non-standard facility values (that is, higher than 23), these messages will be listed as other facility instead of their facility number.

Aggregated statistics

Aggregated statistics are available for different sources and destinations from different levels and upwards: