Add kstat-based Solaris metrics (#1197)

* collector/loadavg_solaris.go: Use libkstat to gather load averages. * go.mod: Added go-kstat. * boot_time_solaris.go: Added. * cpu_solaris.go: Added. * README.md: Updated entries for Solaris. * collector/zfs_solaris.go: Added. * CHANGELOG.md: Added note about kstat-based Solaris metrics. Signed-off-by: Jonathan Davies <jpds@protonmail.com>
2019-01-12 12:33:56 +00:00 · 2019-01-12 12:33:56 +00:00 · e766485286
parent a616953b9a
commit e766485286
9 changed files with 584 additions and 15 deletions
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -10,6 +10,7 @@
 * [CHANGE] Add a limit to the number of in-flight requests #1166
 * [ENHANCEMENT] Add Infiniband counters #1120
 * [FEATURE] Add a flag to disable exporter metrics #1148
+* [FEATURE] Add kstat-based Solaris metrics for boottime, cpu and zfs collectors #1197

 ## 0.17.0 / 2018-11-30

--- a/README.md
+++ b/README.md
@ -29,9 +29,9 @@ Name     | Description | OS
 arp | Exposes ARP statistics from `/proc/net/arp`. | Linux
 bcache | Exposes bcache statistics from `/sys/fs/bcache/`. | Linux
 bonding | Exposes the number of configured and active slaves of Linux bonding interfaces. | Linux
-boottime | Exposes system boot time derived from the `kern.boottime` sysctl. | Darwin, Dragonfly, FreeBSD, NetBSD, OpenBSD
+boottime | Exposes system boot time derived from the `kern.boottime` sysctl. | Darwin, Dragonfly, FreeBSD, NetBSD, OpenBSD, Solaris
 conntrack | Shows conntrack statistics (does nothing if no `/proc/sys/net/netfilter/` present). | Linux
-cpu | Exposes CPU statistics | Darwin, Dragonfly, FreeBSD, Linux
+cpu | Exposes CPU statistics | Darwin, Dragonfly, FreeBSD, Linux, Solaris
 diskstats | Exposes disk I/O statistics. | Darwin, Linux
 edac | Exposes error detection and correction statistics. | Linux
 entropy | Exposes available entropy. | Linux
@ -57,7 +57,7 @@ timex | Exposes selected adjtimex(2) system call stats. | Linux
 uname | Exposes system information as provided by the uname system call. | Linux
 vmstat | Exposes statistics from `/proc/vmstat`. | Linux
 xfs | Exposes XFS runtime statistics. | Linux (kernel 4.4+)
-zfs | Exposes [ZFS](http://open-zfs.org/) performance statistics. | [Linux](http://zfsonlinux.org/)
+zfs | Exposes [ZFS](http://open-zfs.org/) performance statistics. | [Linux](http://zfsonlinux.org/), Solaris

 ### Disabled by default

--- a/collector/boot_time_solaris.go
+++ b/collector/boot_time_solaris.go
@ -0,0 +1,66 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build solaris
+// +build !noboottime
+
+package collector
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/siebenmann/go-kstat"
+)
+
+type bootTimeCollector struct {
+	boottime typedDesc
+}
+
+func init() {
+	registerCollector("boottime", defaultEnabled, newBootTimeCollector)
+}
+
+func newBootTimeCollector() (Collector, error) {
+	return &bootTimeCollector{
+		boottime: typedDesc{
+			prometheus.NewDesc(
+				prometheus.BuildFQName(namespace, "", "boot_time_seconds"),
+				"Unix time of last boot, including microseconds.",
+				nil, nil,
+			), prometheus.GaugeValue},
+	}, nil
+}
+
+// newBootTimeCollector returns a new Collector exposing system boot time on Solaris systems.
+// Update pushes boot time onto ch
+func (c *bootTimeCollector) Update(ch chan<- prometheus.Metric) error {
+	tok, err := kstat.Open()
+	if err != nil {
+		return err
+	}
+
+	defer tok.Close()
+
+	ks, err := tok.Lookup("unix", 0, "system_misc")
+	if err != nil {
+		return err
+	}
+
+	v, err := ks.GetNamed("boot_time")
+	if err != nil {
+		return err
+	}
+
+	ch <- c.boottime.mustNewConstMetric(float64(v.UintVal))
+
+	return nil
+}
--- a/collector/cpu_solaris.go
+++ b/collector/cpu_solaris.go
@ -0,0 +1,140 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build solaris
+// +build !nocpu
+
+package collector
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/siebenmann/go-kstat"
+)
+
+// #include <unistd.h>
+import "C"
+
+type cpuCollector struct {
+	cpu        typedDesc
+	cpuFreq    *prometheus.Desc
+	cpuFreqMax *prometheus.Desc
+}
+
+func init() {
+	registerCollector("cpu", defaultEnabled, NewCpuCollector)
+}
+
+func NewCpuCollector() (Collector, error) {
+	return &cpuCollector{
+		cpu: typedDesc{nodeCPUSecondsDesc, prometheus.CounterValue},
+		cpuFreq: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "frequency_hertz"),
+			"Current cpu thread frequency in hertz.",
+			[]string{"cpu"}, nil,
+		),
+		cpuFreqMax: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "frequency_max_hertz"),
+			"Maximum cpu thread frequency in hertz.",
+			[]string{"cpu"}, nil,
+		),
+	}, nil
+}
+
+func (c *cpuCollector) Update(ch chan<- prometheus.Metric) error {
+	if err := c.updateCPUstats(ch); err != nil {
+		return err
+	}
+	if err := c.updateCPUfreq(ch); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (c *cpuCollector) updateCPUstats(ch chan<- prometheus.Metric) error {
+	ncpus := C.sysconf(C._SC_NPROCESSORS_ONLN)
+
+	tok, err := kstat.Open()
+	if err != nil {
+		return err
+	}
+
+	defer tok.Close()
+
+	for cpu := 0; cpu < int(ncpus); cpu++ {
+		ksCPU, err := tok.Lookup("cpu", cpu, "sys")
+		if err != nil {
+			return err
+		}
+
+		for k, v := range map[string]string{
+			"idle":   "cpu_ticks_idle",
+			"kernel": "cpu_ticks_kernel",
+			"user":   "cpu_ticks_user",
+			"wait":   "cpu_ticks_wait",
+		} {
+			kstatValue, err := ksCPU.GetNamed(v)
+			if err != nil {
+				return err
+			}
+
+			ch <- c.cpu.mustNewConstMetric(float64(kstatValue.UintVal), strconv.Itoa(cpu), k)
+		}
+	}
+	return nil
+}
+
+func (c *cpuCollector) updateCPUfreq(ch chan<- prometheus.Metric) error {
+	ncpus := C.sysconf(C._SC_NPROCESSORS_ONLN)
+
+	tok, err := kstat.Open()
+	if err != nil {
+		return err
+	}
+
+	defer tok.Close()
+
+	for cpu := 0; cpu < int(ncpus); cpu++ {
+		ksCPUInfo, err := tok.Lookup("cpu_info", cpu, fmt.Sprintf("cpu_info%d", cpu))
+		if err != nil {
+			return err
+		}
+		cpuFreqV, err := ksCPUInfo.GetNamed("current_clock_Hz")
+		if err != nil {
+			return err
+		}
+
+		cpuFreqMaxV, err := ksCPUInfo.GetNamed("clock_MHz")
+		if err != nil {
+			return err
+		}
+
+		lcpu := strconv.Itoa(cpu)
+		ch <- prometheus.MustNewConstMetric(
+			c.cpuFreq,
+			prometheus.GaugeValue,
+			float64(cpuFreqV.UintVal),
+			lcpu,
+		)
+		// Multiply by 1e+6 to convert MHz to Hz.
+		ch <- prometheus.MustNewConstMetric(
+			c.cpuFreqMax,
+			prometheus.GaugeValue,
+			float64(cpuFreqMaxV.IntVal)*1e+6,
+			lcpu,
+		)
+	}
+	return nil
+}
--- a/collector/loadavg_solaris.go
+++ b/collector/loadavg_solaris.go
@ -16,21 +16,49 @@
 package collector

 import (
-	"errors"
+	"fmt"
+	"strconv"
+
+	"github.com/siebenmann/go-kstat"
 )

-/*
-// Ensure "hrtime_t" is defined for sys/loadavg.h
-#include <sys/time.h>
-#include <sys/loadavg.h>
-*/
+// #include <sys/param.h>
 import "C"

-func getLoad() ([]float64, error) {
-	var loadavg [3]C.double
-	samples := C.getloadavg(&loadavg[0], 3)
-	if samples != 3 {
-		return nil, errors.New("failed to get load average")
+func kstatToFloat(ks *kstat.KStat, kstatKey string) float64 {
+	kstatValue, err := ks.GetNamed(kstatKey)
+
+	if err != nil {
+		panic(err)
 	}
-	return []float64{float64(loadavg[0]), float64(loadavg[1]), float64(loadavg[2])}, nil
+
+	kstatLoadavg, err := strconv.ParseFloat(
+		fmt.Sprintf("%.2f", float64(kstatValue.UintVal)/C.FSCALE), 64)
+
+	if err != nil {
+		panic(err)
+	}
+
+	return kstatLoadavg
+}
+
+func getLoad() ([]float64, error) {
+	tok, err := kstat.Open()
+	if err != nil {
+		panic(err)
+	}
+
+	defer tok.Close()
+
+	ks, err := tok.Lookup("unix", 0, "system_misc")
+
+	if err != nil {
+		panic(err)
+	}
+
+	loadavg1Min := kstatToFloat(ks, "avenrun_1min")
+	loadavg5Min := kstatToFloat(ks, "avenrun_5min")
+	loadavg15Min := kstatToFloat(ks, "avenrun_15min")
+
+	return []float64{loadavg1Min, loadavg5Min, loadavg15Min}, nil
 }
--- a/collector/zfs_solaris.go
+++ b/collector/zfs_solaris.go
@ -0,0 +1,329 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build solaris
+
+package collector
+
+import (
+	"strings"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/siebenmann/go-kstat"
+)
+
+type zfsCollector struct {
+	abdstatsLinearCount          *prometheus.Desc
+	abdstatsLinearDataSize       *prometheus.Desc
+	abdstatsScatterChunkWaste    *prometheus.Desc
+	abdstatsScatterCount         *prometheus.Desc
+	abdstatsScatterDataSize      *prometheus.Desc
+	abdstatsStructSize           *prometheus.Desc
+	arcstatsAnonSize             *prometheus.Desc
+	arcstatsC                    *prometheus.Desc
+	arcstatsCMax                 *prometheus.Desc
+	arcstatsCMin                 *prometheus.Desc
+	arcstatsDataSize             *prometheus.Desc
+	arcstatsDemandDataHits       *prometheus.Desc
+	arcstatsDemandDataMisses     *prometheus.Desc
+	arcstatsDemandMetadataHits   *prometheus.Desc
+	arcstatsDemandMetadataMisses *prometheus.Desc
+	arcstatsHeaderSize           *prometheus.Desc
+	arcstatsHits                 *prometheus.Desc
+	arcstatsMisses               *prometheus.Desc
+	arcstatsMFUGhostHits         *prometheus.Desc
+	arcstatsMFUGhostSize         *prometheus.Desc
+	arcstatsMFUSize              *prometheus.Desc
+	arcstatsMRUGhostHits         *prometheus.Desc
+	arcstatsMRUGhostSize         *prometheus.Desc
+	arcstatsMRUSize              *prometheus.Desc
+	arcstatsOtherSize            *prometheus.Desc
+	arcstatsP                    *prometheus.Desc
+	arcstatsSize                 *prometheus.Desc
+	zfetchstatsHits              *prometheus.Desc
+	zfetchstatsMisses            *prometheus.Desc
+}
+
+const (
+	zfsCollectorSubsystem = "zfs"
+)
+
+func init() {
+	registerCollector("zfs", defaultEnabled, NewZfsCollector)
+}
+
+func NewZfsCollector() (Collector, error) {
+	return &zfsCollector{
+		abdstatsLinearCount: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "abdstats_linear_count_total"),
+			"ZFS ARC buffer data linear count", nil, nil,
+		),
+		abdstatsLinearDataSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "abdstats_linear_data_bytes"),
+			"ZFS ARC buffer data linear data size", nil, nil,
+		),
+		abdstatsScatterChunkWaste: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "abdstats_scatter_chunk_waste_bytes"),
+			"ZFS ARC buffer data scatter chunk waste", nil, nil,
+		),
+		abdstatsScatterCount: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "abdstats_scatter_count_total"),
+			"ZFS ARC buffer data scatter count", nil, nil,
+		),
+		abdstatsScatterDataSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "abdstats_scatter_data_bytes"),
+			"ZFS ARC buffer data scatter data size", nil, nil,
+		),
+		abdstatsStructSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "abdstats_struct_bytes"),
+			"ZFS ARC buffer data struct size", nil, nil,
+		),
+		arcstatsAnonSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_anon_bytes"),
+			"ZFS ARC anon size", nil, nil,
+		),
+		arcstatsC: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_c_bytes"),
+			"ZFS ARC target size", nil, nil,
+		),
+		arcstatsCMax: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_c_max_bytes"),
+			"ZFS ARC maximum size", nil, nil,
+		),
+		arcstatsCMin: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_c_min_bytes"),
+			"ZFS ARC minimum size", nil, nil,
+		),
+		arcstatsDataSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_data_bytes"),
+			"ZFS ARC data size", nil, nil,
+		),
+		arcstatsDemandDataHits: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_demand_data_hits_total"),
+			"ZFS ARC demand data hits", nil, nil,
+		),
+		arcstatsDemandDataMisses: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_demand_data_misses_total"),
+			"ZFS ARC demand data misses", nil, nil,
+		),
+		arcstatsDemandMetadataHits: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_demand_metadata_hits_total"),
+			"ZFS ARC demand metadata hits", nil, nil,
+		),
+		arcstatsDemandMetadataMisses: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_demand_metadata_misses_total"),
+			"ZFS ARC demand metadata misses", nil, nil,
+		),
+		arcstatsHeaderSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_hdr_bytes"),
+			"ZFS ARC header size", nil, nil,
+		),
+		arcstatsHits: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_hits_total"),
+			"ZFS ARC hits", nil, nil,
+		),
+		arcstatsMisses: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_misses_total"),
+			"ZFS ARC misses", nil, nil,
+		),
+		arcstatsMFUGhostHits: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_mfu_ghost_hits_total"),
+			"ZFS ARC MFU ghost hits", nil, nil,
+		),
+		arcstatsMFUGhostSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_mfu_ghost_size"),
+			"ZFS ARC MFU ghost size", nil, nil,
+		),
+		arcstatsMFUSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_mfu_bytes"),
+			"ZFS ARC MFU size", nil, nil,
+		),
+		arcstatsMRUGhostHits: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_mru_ghost_hits_total"),
+			"ZFS ARC MRU ghost hits", nil, nil,
+		),
+		arcstatsMRUGhostSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_mru_ghost_bytes"),
+			"ZFS ARC MRU ghost size", nil, nil,
+		),
+		arcstatsMRUSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_mru_bytes"),
+			"ZFS ARC MRU size", nil, nil,
+		),
+		arcstatsOtherSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_other_bytes"),
+			"ZFS ARC other size", nil, nil,
+		),
+		arcstatsP: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_p_bytes"),
+			"ZFS ARC MRU target size", nil, nil,
+		),
+		arcstatsSize: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "arcstats_size_bytes"),
+			"ZFS ARC size", nil, nil,
+		),
+		zfetchstatsHits: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "zfetchstats_hits_total"),
+			"ZFS cache fetch hits", nil, nil,
+		),
+		zfetchstatsMisses: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, zfsCollectorSubsystem, "zfetchstats_misses_total"),
+			"ZFS cache fetch misses", nil, nil,
+		),
+	}, nil
+}
+
+func (c *zfsCollector) updateZfsAbdStats(ch chan<- prometheus.Metric) error {
+	var metricType prometheus.ValueType
+
+	tok, err := kstat.Open()
+	if err != nil {
+		return err
+	}
+
+	defer tok.Close()
+
+	ksZFSInfo, err := tok.Lookup("zfs", 0, "abdstats")
+	if err != nil {
+		return err
+	}
+
+	for k, v := range map[string]*prometheus.Desc{
+		"linear_cnt":          c.abdstatsLinearCount,
+		"linear_data_size":    c.abdstatsLinearDataSize,
+		"scatter_chunk_waste": c.abdstatsScatterChunkWaste,
+		"scatter_cnt":         c.abdstatsScatterCount,
+		"scatter_data_size":   c.abdstatsScatterDataSize,
+		"struct_size":         c.abdstatsStructSize,
+	} {
+		ksZFSInfoValue, err := ksZFSInfo.GetNamed(k)
+		if err != nil {
+			return err
+		}
+
+		if strings.HasSuffix(k, "_cnt") {
+			metricType = prometheus.CounterValue
+		} else {
+			metricType = prometheus.GaugeValue
+		}
+
+		ch <- prometheus.MustNewConstMetric(
+			v,
+			metricType,
+			float64(ksZFSInfoValue.UintVal),
+		)
+	}
+
+	return nil
+}
+
+func (c *zfsCollector) updateZfsArcStats(ch chan<- prometheus.Metric) error {
+	var metricType prometheus.ValueType
+
+	tok, err := kstat.Open()
+	if err != nil {
+		return err
+	}
+
+	defer tok.Close()
+
+	ksZFSInfo, err := tok.Lookup("zfs", 0, "arcstats")
+	if err != nil {
+		return err
+	}
+
+	for k, v := range map[string]*prometheus.Desc{
+		"anon_size":              c.arcstatsAnonSize,
+		"c":                      c.arcstatsC,
+		"c_max":                  c.arcstatsCMax,
+		"c_min":                  c.arcstatsCMin,
+		"data_size":              c.arcstatsDataSize,
+		"demand_data_hits":       c.arcstatsDemandDataHits,
+		"demand_data_misses":     c.arcstatsDemandDataMisses,
+		"demand_metadata_hits":   c.arcstatsDemandMetadataHits,
+		"demand_metadata_misses": c.arcstatsDemandMetadataMisses,
+		"hdr_size":               c.arcstatsHeaderSize,
+		"hits":                   c.arcstatsHits,
+		"misses":                 c.arcstatsMisses,
+		"mfu_ghost_hits":         c.arcstatsMFUGhostHits,
+		"mfu_ghost_size":         c.arcstatsMFUGhostSize,
+		"mfu_size":               c.arcstatsMFUSize,
+		"mru_ghost_hits":         c.arcstatsMRUGhostHits,
+		"mru_ghost_size":         c.arcstatsMRUGhostSize,
+		"mru_size":               c.arcstatsMRUSize,
+		"other_size":             c.arcstatsOtherSize,
+		"p":                      c.arcstatsP,
+		"size":                   c.arcstatsSize,
+	} {
+		ksZFSInfoValue, err := ksZFSInfo.GetNamed(k)
+		if err != nil {
+			return err
+		}
+
+		if strings.HasSuffix(k, "_hits") || strings.HasSuffix(k, "_misses") {
+			metricType = prometheus.CounterValue
+		} else {
+			metricType = prometheus.GaugeValue
+		}
+
+		ch <- prometheus.MustNewConstMetric(
+			v,
+			metricType,
+			float64(ksZFSInfoValue.UintVal),
+		)
+	}
+
+	return nil
+}
+
+func (c *zfsCollector) updateZfsFetchStats(ch chan<- prometheus.Metric) error {
+	tok, err := kstat.Open()
+	if err != nil {
+		return err
+	}
+
+	defer tok.Close()
+
+	ksZFSInfo, err := tok.Lookup("zfs", 0, "zfetchstats")
+
+	for k, v := range map[string]*prometheus.Desc{
+		"hits":   c.zfetchstatsHits,
+		"misses": c.zfetchstatsMisses,
+	} {
+		ksZFSInfoValue, err := ksZFSInfo.GetNamed(k)
+		if err != nil {
+			return err
+		}
+
+		ch <- prometheus.MustNewConstMetric(
+			v,
+			prometheus.CounterValue,
+			float64(ksZFSInfoValue.UintVal),
+		)
+	}
+
+	return nil
+}
+
+func (c *zfsCollector) Update(ch chan<- prometheus.Metric) error {
+	if err := c.updateZfsAbdStats(ch); err != nil {
+		return err
+	}
+	if err := c.updateZfsArcStats(ch); err != nil {
+		return err
+	}
+	if err := c.updateZfsFetchStats(ch); err != nil {
+		return err
+	}
+	return nil
+}
--- a/go.mod
+++ b/go.mod
@ -22,6 +22,7 @@ require (
 	github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910
 	github.com/prometheus/common v0.0.0-20181015124227-bcb74de08d37
 	github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d
+	github.com/siebenmann/go-kstat v0.0.0-20160321171754-d34789b79745
 	github.com/sirupsen/logrus v1.1.1 // indirect
 	github.com/soundcloud/go-runit v0.0.0-20150630195641-06ad41a06c4a
 	golang.org/x/crypto v0.0.0-20181009213950-7c1a557ab941 // indirect
--- a/go.sum
+++ b/go.sum
@ -45,6 +45,8 @@ github.com/prometheus/common v0.0.0-20181015124227-bcb74de08d37 h1:Y7YdJ9Xb3MoQO
 github.com/prometheus/common v0.0.0-20181015124227-bcb74de08d37/go.mod h1:daVV7qP5qjZbuso7PdcryaAu0sAZbrN9i7WWcTMWvro=
 github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d h1:GoAlyOgbOEIFdaDqxJVlbOQ1DtGmZWs/Qau0hIlk+WQ=
 github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
+github.com/siebenmann/go-kstat v0.0.0-20160321171754-d34789b79745 h1:IuH7WumZNax0D+rEqmy2TyhKCzrtMGqbZO0b8rO00JA=
+github.com/siebenmann/go-kstat v0.0.0-20160321171754-d34789b79745/go.mod h1:G81aIFAMS9ECrwBYR9YxhlPjWgrItd+Kje78O6+uqm8=
 github.com/sirupsen/logrus v1.1.1 h1:VzGj7lhU7KEB9e9gMpAV/v5XT2NVSvLJhJLCWbnkgXg=
 github.com/sirupsen/logrus v1.1.1/go.mod h1:zrgwTnHtNr00buQ1vSptGe8m1f/BbgsPukg8qsT7A+A=
 github.com/soundcloud/go-runit v0.0.0-20150630195641-06ad41a06c4a h1:os5OBNhwOwybXZMNLqT96XqtjdTtwRFw2w08uluvNeI=
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@ -50,6 +50,8 @@ github.com/prometheus/procfs/nfs
 github.com/prometheus/procfs/sysfs
 github.com/prometheus/procfs/xfs
 github.com/prometheus/procfs/internal/util
+# github.com/siebenmann/go-kstat v0.0.0-20160321171754-d34789b79745
+github.com/siebenmann/go-kstat
 # github.com/sirupsen/logrus v1.1.1
 github.com/sirupsen/logrus
 # github.com/soundcloud/go-runit v0.0.0-20150630195641-06ad41a06c4a