Statistics of syslog-ng
The syslog-ng OSE application collects various statistics and measures different metrics about the messages it receives and delivers. These metrics are collected into different counters, depending on the configuration of syslog-ng OSE. The stats-level() global option determines exactly which statistics syslog-ng OSE collects. You can access these statistics and metrics using the following methods.
Recommended: Structured, selective methods:
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Using the syslog-ng-ctl query command.
Legacy: Unstructured, bulk methods:
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Using the internal() source.
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Using the syslog-ng-ctl stats command.
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Use the socat application: echo STATS | socat -vv UNIX-CONNECT:/opt/syslog-ng/var/run/syslog-ng.ctl -
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If you have an OpenBSD-style netcat application installed, use the echo STATS | nc -U /opt/syslog-ng/var/run/syslog-ng.ctl command. Note that the netcat included in most Linux distributions is a GNU-style version that is not suitable to query the statistics of syslog-ng.
Metrics and counters of syslog-ng OSE
You can list all active metrics on your syslog-ng OSE host using the following command (this lists the metrics, without their current values): syslog-ng-ctl query list "*"
To list the metrics and their values, use the following command: syslog-ng-ctl query get "*"
The displayed metrics have the following structure.
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The type of the object (for example dst.file, tag, src.facility)
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The ID of the object used in the syslog-ng configuration file, for example d_internal or source.src_tcp. The #0 part means that this is the first destination in the destination group.
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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.
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The status of the object. One of the following:
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a - active. At the time of quering the statistics, the source or the destination was still alive (it continuously received statistical data).
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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:
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host: source host, from stats-level(2)
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sender: sender host, from stats-level(3)
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program: program, from stats-level(3)
Example: Dynamic counters
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 syslog-ng OSE, 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.
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o - This object was once active, but stopped receiving messages. (For example a dynamic object may disappear and become orphan.)
NOTE: The syslog-ng OSE application stores the statistics of the objects when syslog-ng OSE is reloaded. However, if the configuration of syslog-ng OSE was changed since the last reload, the statistics of orphaned objects are deleted.
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The type of the statistics:
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processed: The number of messages that successfully reached their destination driver. Note that this does not necessarily mean that the destination driver successfully delivered the messages (for example, written to disk or sent to a remote server).
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dropped: The number of dropped messages — syslog-ng OSE could not send the messages to the destination and the output buffer got full, so messages were dropped by the destination driver, or syslog-ng OSE dropped the message for some other reason (for example, a parsing error).
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queued: The number of messages passed to the message queue of the destination driver, waiting to be sent to the destination.
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suppressed: The number of suppressed messages (if the suppress() feature is enabled).
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stamp: The UNIX timestamp of the last message sent to the destination.
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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
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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 that the memory usage (size) of queues does not equal to the memory usage (size) of the log messages in syslog-ng OSE. 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.
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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
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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 that 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
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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 syslog-ng OSE 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 syslog-ng OSE 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.
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The number of such messages.
Availability of statistics
Certain statistics are available only if the stats-level() global option is set to a higher value.
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Level 0 collects only statistics about the sources and destinations.
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Level 1 contains details about the different connections and log files, but has a slight memory overhead.
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Level 2 contains detailed statistics based on the hostname.
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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.
Log statistics from the internal() source
If the stats-freq() global option is higher than 0, syslog-ng OSE periodically sends a log statistics message. This message contains statistics about the received messages, and about any lost messages since the last such message. It includes a processed entry for every source and destination, listing the number of messages received or sent, and a dropped entry including the IP address of the server for every destination where syslog-ng has lost messages. The center(received) entry shows the total number of messages received from every configured sources.
The following is a sample log statistics message for a configuration that has a single source (s_local) and a network and a local file destination (d_network and d_local, respectively). All incoming messages are sent to both destinations.
Log statistics;
dropped='tcp(AF_INET(192.168.10.1:514))=6439',
processed='center(received)=234413',
processed='destination(d_tcp)=234413',
processed='destination(d_local)=234413',
processed='source(s_local)=234413'
The statistics include a list of source groups and destinations, as well as the number of processed messages for each. You can control the verbosity of the statistics using the stats-level() global option. The following is an example output.
src.internal;s_all#0;;a;processed;6445 src.internal;s_all#0;;a;stamp;1268989330 destination;df_auth;;a;processed;404 destination;df_news_dot_notice;;a;processed;0 destination;df_news_dot_err;;a;processed;0 destination;d_ssb;;a;processed;7128 destination;df_uucp;;a;processed;0 source;s_all;;a;processed;7128 destination;df_mail;;a;processed;0 destination;df_user;;a;processed;1 destination;df_daemon;;a;processed;1 destination;df_debug;;a;processed;15 destination;df_messages;;a;processed;54 destination;dp_xconsole;;a;processed;671 dst.tcp;d_network#0;10.50.0.111:514;a;dropped;5080 dst.tcp;d_network#0;10.50.0.111:514;a;processed;7128 dst.tcp;d_network#0;10.50.0.111:514;a;queued;2048 destination;df_syslog;;a;processed;6724 destination;df_facility_dot_warn;;a;processed;0 destination;df_news_dot_crit;;a;processed;0 destination;df_lpr;;a;processed;0 destination;du_all;;a;processed;0 destination;df_facility_dot_info;;a;processed;0 center;;received;a;processed;0 destination;df_kern;;a;processed;70 center;;queued;a;processed;0 destination;df_facility_dot_err;;a;processed;0
The statistics are semicolon separated: every line contains statistics for a particular object (for example source, destination, tag, and so on). The statistics have the following fields:
To reset the statistics to zero, use the following command: syslog-ng-ctl stats --reset
Multithreading and scaling in syslog-ng OSE
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