ifdef::env-github[]
NOTE: For the best reading experience,
please view this documentation at https://www.elastic.co/guide/en/apm/agent/ruby[elastic.co]
endif::[]

[[metrics]]
== Metrics

The Ruby agent tracks various system and application metrics.
These metrics will be sent regularly to the APM Server and from there to Elasticsearch.
You can adjust the interval by setting <<config-metrics-interval,`metrics_interval`>>.

The metrics will be stored in the `apm-*` index and have the `processor.event` property set to `metric`.

**Note:** Metrics from the Ruby agent are Linux only for now.

[float]
[[metric-system.cpu.total.norm.pct]]
=== `system.cpu.total.norm.pct`

* *Type:* Float
* *Format:* Percent

The percentage of CPU time in states other than Idle and IOWait,
normalised by the number of cores.

[float]
[[metric-system.memory.total]]
=== `system.memory.total`

* *Type:* Long
* *Format:* Bytes

The total memory of the system in bytes.

[float]
[[metric-system.memory.actual.free]]
=== `system.memory.actual.free`

* *Type:* Long
* *Format:* Bytes

Free memory of the system in bytes.

[float]
[[metric-system.process.cpu.total.norm.pct]]
=== `system.process.cpu.total.norm.pct`

* *Type:* Float
* *Format:* Percent

The percentage of CPU time spent by the process since the last event.
This value is normalized by the number of CPU cores and it ranges from 0 to 100%.

[float]
[[metric-system.process.memory.size]]
=== `system.process.memory.size`

* *Type:* Long
* *Format:* Bytes

The total virtual memory the process has.

[float]
[[metric-system.process.memory.rss.bytes]]
=== `system.process.memory.rss.bytes`

* *Type:* Long
* *Format:* Bytes

The Resident Set Size,
the amount of memory the process occupies in main memory (RAM).