# zfs
Plugin: freebsd.plugin
Module: zfs
## Overview
Collect metrics for ZFS filesystem
The plugin uses `sysctl` function to collect necessary data.
This collector is supported on all platforms.
This collector supports collecting metrics from multiple instances of this integration, including remote instances.
### Default Behavior
#### Auto-Detection
This integration doesn't support auto-detection.
#### Limits
The default configuration for this integration does not impose any limits on data collection.
#### Performance Impact
The default configuration for this integration is not expected to impose a significant performance impact on the system.
## Metrics
Metrics grouped by *scope*.
The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.
### Per zfs instance
These metrics show detailed information about ZFS filesystem.
This scope has no labels.
Metrics:
| Metric | Dimensions | Unit |
|:------|:----------|:----|
| zfs.arc_size | arcsz, target, min, max | MiB |
| zfs.l2_size | actual, size | MiB |
| zfs.reads | arc, demand, prefetch, metadata, l2 | reads/s |
| zfs.bytes | read, write | KiB/s |
| zfs.hits | hits, misses | percentage |
| zfs.hits_rate | hits, misses | events/s |
| zfs.dhits | hits, misses | percentage |
| zfs.dhits_rate | hits, misses | events/s |
| zfs.phits | hits, misses | percentage |
| zfs.phits_rate | hits, misses | events/s |
| zfs.mhits | hits, misses | percentage |
| zfs.mhits_rate | hits, misses | events/s |
| zfs.l2hits | hits, misses | percentage |
| zfs.l2hits_rate | hits, misses | events/s |
| zfs.list_hits | mfu, mfu_ghost, mru, mru_ghost | hits/s |
| zfs.arc_size_breakdown | recent, frequent | percentage |
| zfs.memory_ops | throttled | operations/s |
| zfs.important_ops | evict_skip, deleted, mutex_miss, hash_collisions | operations/s |
| zfs.actual_hits | hits, misses | percentage |
| zfs.actual_hits_rate | hits, misses | events/s |
| zfs.demand_data_hits | hits, misses | percentage |
| zfs.demand_data_hits_rate | hits, misses | events/s |
| zfs.prefetch_data_hits | hits, misses | percentage |
| zfs.prefetch_data_hits_rate | hits, misses | events/s |
| zfs.hash_elements | current, max | elements |
| zfs.hash_chains | current, max | chains |
| zfs.trim_bytes | TRIMmed | bytes |
| zfs.trim_requests | successful, failed, unsupported | requests |
## Alerts
The following alerts are available:
| Alert name | On metric | Description |
|:------------|:----------|:------------|
| [ zfs_memory_throttle ](https://github.com/netdata/netdata/blob/master/health/health.d/zfs.conf) | zfs.memory_ops | number of times ZFS had to limit the ARC growth in the last 10 minutes |
## Setup
### Prerequisites
No action required.
### Configuration
#### File
The configuration file name for this integration is `netdata.conf`.
Configuration for this specific integration is located in the `[plugin:freebsd:zfs_arcstats]` section within that file.
The file format is a modified INI syntax. The general structure is:
```ini
[section1]
option1 = some value
option2 = some other value
[section2]
option3 = some third value
```
You can edit the configuration file using the `edit-config` script from the
Netdata [config directory](https://github.com/netdata/netdata/blob/master/docs/configure/nodes.md#the-netdata-config-directory).
```bash
cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config netdata.conf
```
#### Options
Config options
| Name | Description | Default | Required |
|:----|:-----------|:-------|:--------:|
| show zero charts | Do not show charts with zero metrics. | no | no |