Add dataset metrics to zfs input (#8383)

plugins/inputs/zfs/README.md

@@ -2,7 +2,7 @@
 
 This ZFS plugin provides metrics from your ZFS filesystems. It supports ZFS on
 Linux and FreeBSD. It gets ZFS stat from `/proc/spl/kstat/zfs` on Linux and
-from `sysctl` and `zpool` on FreeBSD.
+from `sysctl`, 'zfs' and `zpool` on FreeBSD.
 
 ### Configuration:
 
@@ -22,18 +22,24 @@ from `sysctl` and `zpool` on FreeBSD.
 
   ## By default, don't gather zpool stats
   # poolMetrics = false
+
+  ## By default, don't gather dataset stats
+  # datasetMetrics = false
 ```
 
 ### Measurements & Fields:
 
-By default this plugin collects metrics about ZFS internals and pool.
+By default this plugin collects metrics about ZFS internals pool and dataset.
 These metrics are either counters or measure sizes
 in bytes. These metrics will be in the `zfs` measurement with the field
 names listed bellow.
 
 If `poolMetrics` is enabled then additional metrics will be gathered for
 each pool.
 
+If `datasetMetrics` is enabled then additional metrics will be gathered for
+each dataset.
+
 - zfs
     With fields listed bellow.
 
@@ -206,21 +212,34 @@ On FreeBSD:
     - size (integer, bytes)
     - fragmentation (integer, percent)
 
+#### Dataset Metrics (optional, only on FreeBSD)
+
+- zfs_dataset
+    - avail (integer, bytes)
+    - used (integer, bytes)
+    - usedsnap (integer, bytes
+    - usedds (integer, bytes)
+
 ### Tags:
 
 - ZFS stats (`zfs`) will have the following tag:
     - pools - A `::` concatenated list of all ZFS pools on the machine.
+    - datasets - A `::` concatenated list of all ZFS datasets on the machine.
 
 - Pool metrics (`zfs_pool`) will have the following tag:
     - pool - with the name of the pool which the metrics are for.
     - health - the health status of the pool. (FreeBSD only)
 
+- Dataset metrics (`zfs_dataset`) will have the following tag:
+    - dataset - with the name of the dataset which the metrics are for.
+
 ### Example Output:
 
 ```
 $ ./telegraf --config telegraf.conf --input-filter zfs --test
 * Plugin: zfs, Collection 1
 > zfs_pool,health=ONLINE,pool=zroot allocated=1578590208i,capacity=2i,dedupratio=1,fragmentation=1i,free=64456531968i,size=66035122176i 1464473103625653908
+> zfs_dataset,dataset=zata avail=10741741326336,used=8564135526400,usedsnap=0,usedds=90112
 > zfs,pools=zroot arcstats_allocated=4167764i,arcstats_anon_evictable_data=0i,arcstats_anon_evictable_metadata=0i,arcstats_anon_size=16896i,arcstats_arc_meta_limit=10485760i,arcstats_arc_meta_max=115269568i,arcstats_arc_meta_min=8388608i,arcstats_arc_meta_used=51977456i,arcstats_c=16777216i,arcstats_c_max=41943040i,arcstats_c_min=16777216i,arcstats_data_size=0i,arcstats_deleted=1699340i,arcstats_demand_data_hits=14836131i,arcstats_demand_data_misses=2842945i,arcstats_demand_hit_predictive_prefetch=0i,arcstats_demand_metadata_hits=1655006i,arcstats_demand_metadata_misses=830074i,arcstats_duplicate_buffers=0i,arcstats_duplicate_buffers_size=0i,arcstats_duplicate_reads=123i,arcstats_evict_l2_cached=0i,arcstats_evict_l2_eligible=332172623872i,arcstats_evict_l2_ineligible=6168576i,arcstats_evict_l2_skip=0i,arcstats_evict_not_enough=12189444i,arcstats_evict_skip=195190764i,arcstats_hash_chain_max=2i,arcstats_hash_chains=10i,arcstats_hash_collisions=43134i,arcstats_hash_elements=2268i,arcstats_hash_elements_max=6136i,arcstats_hdr_size=565632i,arcstats_hits=16515778i,arcstats_l2_abort_lowmem=0i,arcstats_l2_asize=0i,arcstats_l2_cdata_free_on_write=0i,arcstats_l2_cksum_bad=0i,arcstats_l2_compress_failures=0i,arcstats_l2_compress_successes=0i,arcstats_l2_compress_zeros=0i,arcstats_l2_evict_l1cached=0i,arcstats_l2_evict_lock_retry=0i,arcstats_l2_evict_reading=0i,arcstats_l2_feeds=0i,arcstats_l2_free_on_write=0i,arcstats_l2_hdr_size=0i,arcstats_l2_hits=0i,arcstats_l2_io_error=0i,arcstats_l2_misses=0i,arcstats_l2_read_bytes=0i,arcstats_l2_rw_clash=0i,arcstats_l2_size=0i,arcstats_l2_write_buffer_bytes_scanned=0i,arcstats_l2_write_buffer_iter=0i,arcstats_l2_write_buffer_list_iter=0i,arcstats_l2_write_buffer_list_null_iter=0i,arcstats_l2_write_bytes=0i,arcstats_l2_write_full=0i,arcstats_l2_write_in_l2=0i,arcstats_l2_write_io_in_progress=0i,arcstats_l2_write_not_cacheable=380i,arcstats_l2_write_passed_headroom=0i,arcstats_l2_write_pios=0i,arcstats_l2_write_spa_mismatch=0i,arcstats_l2_write_trylock_fail=0i,arcstats_l2_writes_done=0i,arcstats_l2_writes_error=0i,arcstats_l2_writes_lock_retry=0i,arcstats_l2_writes_sent=0i,arcstats_memory_throttle_count=0i,arcstats_metadata_size=17014784i,arcstats_mfu_evictable_data=0i,arcstats_mfu_evictable_metadata=16384i,arcstats_mfu_ghost_evictable_data=5723648i,arcstats_mfu_ghost_evictable_metadata=10709504i,arcstats_mfu_ghost_hits=1315619i,arcstats_mfu_ghost_size=16433152i,arcstats_mfu_hits=7646611i,arcstats_mfu_size=305152i,arcstats_misses=3676993i,arcstats_mru_evictable_data=0i,arcstats_mru_evictable_metadata=0i,arcstats_mru_ghost_evictable_data=0i,arcstats_mru_ghost_evictable_metadata=80896i,arcstats_mru_ghost_hits=324250i,arcstats_mru_ghost_size=80896i,arcstats_mru_hits=8844526i,arcstats_mru_size=16693248i,arcstats_mutex_miss=354023i,arcstats_other_size=34397040i,arcstats_p=4172800i,arcstats_prefetch_data_hits=0i,arcstats_prefetch_data_misses=0i,arcstats_prefetch_metadata_hits=24641i,arcstats_prefetch_metadata_misses=3974i,arcstats_size=51977456i,arcstats_sync_wait_for_async=0i,vdev_cache_stats_delegations=779i,vdev_cache_stats_hits=323123i,vdev_cache_stats_misses=59929i,zfetchstats_hits=0i,zfetchstats_max_streams=0i,zfetchstats_misses=0i 1464473103634124908
 ```
 

plugins/inputs/zfs/zfs.go

@@ -1,14 +1,22 @@
 package zfs
 
+import (
+	"github.com/influxdata/telegraf"
+)
+
 type Sysctl func(metric string) ([]string, error)
 type Zpool func() ([]string, error)
+type Zdataset func(properties []string) ([]string, error)
 
 type Zfs struct {
-	KstatPath    string
-	KstatMetrics []string
-	PoolMetrics  bool
-	sysctl       Sysctl
-	zpool        Zpool
+	KstatPath      string
+	KstatMetrics   []string
+	PoolMetrics    bool
+	DatasetMetrics bool
+	sysctl         Sysctl
+	zpool          Zpool
+	zdataset       Zdataset
+	Log            telegraf.Logger `toml:"-"`
 }
 
 var sampleConfig = `
@@ -24,12 +32,14 @@ var sampleConfig = `
   #   "dmu_tx", "fm", "vdev_mirror_stats", "zfetchstats", "zil"]
   ## By default, don't gather zpool stats
   # poolMetrics = false
+  ## By default, don't gather zdataset stats
+  # datasetMetrics = false
 `
 
 func (z *Zfs) SampleConfig() string {
 	return sampleConfig
 }
 
 func (z *Zfs) Description() string {
-	return "Read metrics of ZFS from arcstats, zfetchstats, vdev_cache_stats, and pools"
+	return "Read metrics of ZFS from arcstats, zfetchstats, vdev_cache_stats, pools and datasets"
 }

plugins/inputs/zfs/zfs_freebsd.go

@@ -87,6 +87,47 @@ func (z *Zfs) gatherPoolStats(acc telegraf.Accumulator) (string, error) {
 	return strings.Join(pools, "::"), nil
 }
 
+func (z *Zfs) gatherDatasetStats(acc telegraf.Accumulator) (string, error) {
+	properties := []string{"name", "avail", "used", "usedsnap", "usedds"}
+
+	lines, err := z.zdataset(properties)
+	if err != nil {
+		return "", err
+	}
+
+	datasets := []string{}
+	for _, line := range lines {
+		col := strings.Split(line, "\t")
+
+		datasets = append(datasets, col[0])
+	}
+
+	if z.DatasetMetrics {
+		for _, line := range lines {
+			col := strings.Split(line, "\t")
+			if len(col) != len(properties) {
+				z.Log.Warnf("Invalid number of columns for line: %s", line)
+				continue
+			}
+
+			tags := map[string]string{"dataset": col[0]}
+			fields := map[string]interface{}{}
+
+			for i, key := range properties[1:] {
+				value, err := strconv.ParseInt(col[i+1], 10, 64)
+				if err != nil {
+					return "", fmt.Errorf("Error parsing %s %q: %s", key, col[i+1], err)
+				}
+				fields[key] = value
+			}
+
+			acc.AddFields("zfs_dataset", fields, tags)
+		}
+	}
+
+	return strings.Join(datasets, "::"), nil
+}
+
 func (z *Zfs) Gather(acc telegraf.Accumulator) error {
 	kstatMetrics := z.KstatMetrics
 	if len(kstatMetrics) == 0 {
@@ -99,6 +140,11 @@ func (z *Zfs) Gather(acc telegraf.Accumulator) error {
 		return err
 	}
 	tags["pools"] = poolNames
+	datasetNames, err := z.gatherDatasetStats(acc)
+	if err != nil {
+		return err
+	}
+	tags["datasets"] = datasetNames
 
 	fields := make(map[string]interface{})
 	for _, metric := range kstatMetrics {
@@ -137,15 +183,20 @@ func zpool() ([]string, error) {
 	return run("zpool", []string{"list", "-Hp", "-o", "name,health,size,alloc,free,fragmentation,capacity,dedupratio"}...)
 }
 
+func zdataset(properties []string) ([]string, error) {
+	return run("zfs", []string{"list", "-Hp", "-o", strings.Join(properties, ",")}...)
+}
+
 func sysctl(metric string) ([]string, error) {
 	return run("sysctl", []string{"-q", fmt.Sprintf("kstat.zfs.misc.%s", metric)}...)
 }
 
 func init() {
 	inputs.Add("zfs", func() telegraf.Input {
 		return &Zfs{
-			sysctl: sysctl,
-			zpool:  zpool,
+			sysctl:   sysctl,
+			zpool:    zpool,
+			zdataset: zdataset,
 		}
 	})
 }

plugins/inputs/zfs/zfs_freebsd_test.go

@@ -31,6 +31,18 @@ func mock_zpool_unavail() ([]string, error) {
 	return zpool_output_unavail, nil
 }
 
+// $ zfs list -Hp -o name,avail,used,usedsnap,usedds
+var zdataset_output = []string{
+	"zata    10741741326336  8564135526400   0       90112",
+	"zata/home       10741741326336  2498560 212992  2285568",
+	"zata/import     10741741326336  196608  81920   114688",
+	"zata/storage    10741741326336  8556084379648   3601138999296   4954945380352",
+}
+
+func mock_zdataset() ([]string, error) {
+	return zdataset_output, nil
+}
+
 // sysctl -q kstat.zfs.misc.arcstats
 
 // sysctl -q kstat.zfs.misc.vdev_cache_stats
@@ -126,6 +138,39 @@ func TestZfsPoolMetrics_unavail(t *testing.T) {
 	acc.AssertContainsTaggedFields(t, "zfs_pool", poolMetrics, tags)
 }
 
+func TestZfsDatasetMetrics(t *testing.T) {
+	var acc testutil.Accumulator
+
+	z := &Zfs{
+		KstatMetrics: []string{"vdev_cache_stats"},
+		sysctl:       mock_sysctl,
+		zdataset:     mock_zdataset,
+	}
+	err := z.Gather(&acc)
+	require.NoError(t, err)
+
+	require.False(t, acc.HasMeasurement("zfs_dataset"))
+	acc.Metrics = nil
+
+	z = &Zfs{
+		KstatMetrics:   []string{"vdev_cache_stats"},
+		DatasetMetrics: true,
+		sysctl:         mock_sysctl,
+		zdataset:       mock_zdataset,
+	}
+	err = z.Gather(&acc)
+	require.NoError(t, err)
+
+	//one pool, all metrics
+	tags := map[string]string{
+		"dataset": "zata",
+	}
+
+	datasetMetrics := getZataDatasetMetrics()
+
+	acc.AssertContainsTaggedFields(t, "zfs_dataset", datasetMetrics, tags)
+}
+
 func TestZfsGeneratesMetrics(t *testing.T) {
 	var acc testutil.Accumulator
 
@@ -178,6 +223,15 @@ func getTemp2PoolMetrics() map[string]interface{} {
 	}
 }
 
+func getZataDatasetMetrics() map[string]interface{} {
+	return map[string]interface{}{
+		"avail":    int64(10741741326336),
+		"used":     int64(8564135526400),
+		"usedsnap": int64(0),
+		"usedds":   int64(90112),
+	}
+}
+
 func getKstatMetricsVdevOnly() map[string]interface{} {
 	return map[string]interface{}{
 		"vdev_cache_stats_misses":      int64(87789),