# Metrics reference The following list shows the metrics available in AxoSyslog. AxoSyslog provides detailed metrics about its performance and status for observability and monitoring. We recommend using Prometheus to scrape these metrics, see [Collect metrics with Prometheus](../../docs/axosyslog-core/chapter-log-statistics/prometheus-exporter/index.md) for details. To display the current metrics locally in Prometheus-compatible format, run: ``` syslog-ng-ctl stats prometheus ``` Note that which metrics are shown depends on the current value of the [`stats(level())` global option](../../docs/axosyslog-core/chapter-global-options/reference-options/index.md#global-option-stats-level) (you can list the available metrics by running `syslog-ng --metrics-registry`). For details on what the metrics mean, see [Metrics reference](../../docs/axosyslog-core/chapter-log-statistics/metrics-reference/index.md). Note * Metrics that have the `_total` suffix reset to zero when AxoSyslog is restarted. Reloading AxoSyslog doesn’t cause a reset. * Different metrics are available on different [`stats(level())`](../../docs/axosyslog-core/chapter-global-options/reference-options/index.md#global-option-stats-level). ## classified_events_total _Description_ : Default metric of the [`metrics-probe()`](../../docs/axosyslog-core/chapter-parsers/metrics-probe/index.md) parser. ## disk_queue_capacity_bytes _Description_ : Maximal size of the disk queue (in bytes), as set in the `capacity-bytes()` disk-buffer option. ## disk_queue_capacity _Description_ : The size of the overflow queue of the destination, as set in the `flow-control-window-size()` disk-buffer option. ## disk_queue_dir_available_bytes _Description_ : The size of the space available in the directories where disk-buffer files are stored (including directories storing abandoned disk-buffers), in bytes. ## disk_queue_disk_allocated_bytes _Description_ : The actual size of the disk-buffer files, in bytes. ## disk_queue_disk_usage_bytes _Description_ : Total size of data waiting in each disk-buffer, in bytes. ## disk_queue_events _Description_ : Number of messages waiting in each disk-buffer by destination. ## disk_queue_memory_usage_bytes _Description_ : Amount of memory used for caching disk-buffers, in bytes. ## disk_queue_processed_events_total _Description_ : The number of events processed since startup by each disk-buffer. ## event_processing_latency_seconds _Description_ : Histogram of the latency (time from receiving the message to fully processing it), from the source or destination perspective. ## events_allocated_bytes _Description_ : The total amount of memory used by log messages in AxoSyslog. ## filtered_events_total _Description_ : The total number of messages that matched and didn’t match a filter, for each filter in the configuration file. ## input_event_bytes_total _Description_ : Incoming log messages processed by each source, measured in bytes. ## input_events_total _Description_ : Number of incoming log messages processed by each source. ## input_transport_errors_total _Description_ : Number of various transport errors that prevent AxoSyslog from ingesting messages, for example, TLS handshake errors or syslog framing errors. Labels include the source `id`, `peer_address`, and the `reason` for the error. ``` syslogng_input_transport_errors_total{address="127.0.0.1:5513",driver="syslog",peer_address="127.0.0.1",reason="invalid-frame-header",transport="tcp"} 1 syslogng_input_transport_errors_total{address="127.0.0.1:5515",driver="syslog",id="s_tls_req#0",peer_address="127.0.0.1",reason="tls-handshake",tls_error="0A0000C7",tls_error_string="SSL routines::peer did not return a certificate",transport="tls"} 1 ``` ## input_window_available _Description_ : Available on `stats(level(3))`. Shows the current size of the flow-control window (how much is still free from `log-iw-size()`). ## input_window_capacity _Description_ : Available on `stats(level(3))`. Shows the value of `log-iw-size()` (the size of the flow-control window). ## input_window_full_total _Description_ : The total number of input window full events, for the entire configuration. These events cause AxoSyslog to throttle the source. Available on `stats(level(1))`. ## internal_events_queue_capacity _Description_ : The internal queue size of the [`internal()`](../../docs/axosyslog-core/chapter-sources/configuring-sources-internal/index.md) source. ## internal_events_total _Description_ : The number of messages the [`internal()`](../../docs/axosyslog-core/chapter-sources/configuring-sources-internal/index.md) source has queued, processed, or dropped. ## io_worker_latency_seconds _Description_ : Shows how overloaded the IO workers of AxoSyslog are. ## last_config_file_modification_timestamp_seconds _Description_ : The date when the configuration file was last modified. ## last_config_reload_timestamp_seconds _Description_ : The date when the AxoSyslog configuration was last reloaded. If it differs from `last_successful_config_reload_timestamp_seconds`, reloading the configuration has failed. ## last_successful_config_reload_timestamp_seconds _Description_ : The date when the AxoSyslog configuration was last reloaded successfully. ## mainloop_io_worker_roundtrip_latency_seconds _Description_ : Shows how overloaded the main AxoSyslog loop is (how much time it takes to start a new worker). Values close to 0 are good, high values indicate high load or processing bottleneck. ## memory_queue_capacity _Description_ : Shows the capacity (maximum possible size) of each queue. Note that this metric publishes `log-fifo-size()`, which only limits non-flow-controlled messages. Messages coming from flow-controlled paths aren’t limited by `log-fifo-size()`, but by the `log-iw-size()` of their corresponding source. For metrics on `log-iw-size()`, see [`input_window_available`](../../docs/axosyslog-core/chapter-log-statistics/metrics-reference/index.md#input_window_available) and [`input_window_capacity`](../../docs/axosyslog-core/chapter-log-statistics/metrics-reference/index.md#input_window_capacity). ## memory_queue_events _Description_ : Number of messages waiting in each memory queue by destination. ## memory_queue_memory_usage_bytes _Description_ : Total bytes of data waiting in each memory queue. ## memory_queue_processed_events_total _Description_ : The number of events processed since startup by each queue. ## output_active_worker_partitions _Description_ : The number of active partitions when `worker-partition-autoscaling()` is set to `yes`. ## output_batch_size_bytes _Description_ : Histogram-style metrics for the destination. ## output_batch_size_events _Description_ : Histogram-style metrics for the destination. ## output_batch_timedout_total _Description_ : For destinations that use batching, it shows the number of batches that were sent because of timeout (either `batch-timeout()` or `batch-idle-timeout()` expired). ## output_event_bytes_total _Description_ : Log messages sent to each destination, measured in bytes. ## output_event_latency_seconds _Description_ : Histogram of the latency: time from receiving the message to delivering it to the destination. ## output_event_retries_total _Description_ : Shows the number of events when AxoSyslog retried sending a message. ## output_event_size_bytes _Description_ : Histogram-style metrics for the destination. ## output_events_total _Description_ : Number of log messages sent to each destination, showing sent and dropped messages. ## output_grpc_requests_total _Description_ : The total number of gRPC requests. ## output_http_requests_total _Description_ : Available on `stats(level(1))` The total number of HTTP requests. ## output_request_latency_seconds _Description_ : Histogram-style metrics for the destination. ## output_unreachable _Description_ : A bool-like metric, which shows whether a destination is reachable or not. ## output_workers _Description_ : The number of workers configured for each destination. ## parallelize_failed_events_total _Description_ : The number of events that [`parallelize()`](../../docs/axosyslog-core/chapter-nonsequential-processing/index.md) couldn’t process in parallel. Such messages were sent without parallelization. A high number of such events can signal a configuration issue or a bottleneck. ## parallelized_assigned_events_total _Description_ : The number of events each worker has received when using [`parallelize()`](../../docs/axosyslog-core/chapter-nonsequential-processing/index.md). Can show if the workers receive the load unevenly. ## parallelized_processed_events_total _Description_ : The number of events processed using [`parallelize()`](../../docs/axosyslog-core/chapter-nonsequential-processing/index.md). ## parsed_events_total _Description_ : Shows the number of messages processed by each parser. ## route_egress_total _Description_ : The number of messages delivered by each [named log path](../../docs/axosyslog-core/chapter-routing-filters/logpath/index.md#name-log-path). ## route_ingress_total _Description_ : The number of messages entering each [named log path](../../docs/axosyslog-core/chapter-routing-filters/logpath/index.md#name-log-path). ## scratch_buffers_bytes _Description_ : The number of bytes allocated to internal string buffers. ## scratch_buffers_count _Description_ : The number of allocated internal string buffers. ## socket_connections _Description_ : Number of active connections for the sources. ## socket_max_connections _Description_ : Maximum permitted number of connections for the sources. ## socket_receive_buffer_max_bytes _Description_ : The maximal size socket receive buffer in bytes, as configured in the `so-rcvbuf()` option of the destination. ## socket_receive_buffer_used_bytes _Description_ : The number of bytes used from the socket receive buffer. ## socket_receive_dropped_packets_total _Description_ : Number of UDP packets dropped by the OS before processing. ## socket_rejected_connections_total _Description_ : The number of connections rejected because the `max-connections()` limit of the source was reached, for each source. ## stats_level _Description_ : Shows the current verbosity [`level()`](../../docs/axosyslog-core/chapter-global-options/reference-options/index.md#global-option-stats-level) of statistics and metrics. ## tagged_events_total _Description_ : The number of messages marked with a [tag](../../docs/axosyslog-core/chapter-manipulating-messages/modifying-messages/rewrite-tags/index.md), for each tag. (Every message automatically has the tag of its source in `.source.` format.) Last modified May 4, 2026: [Review fix (3f22dae8)]()