Export bucket usage counts as part of bucket metrics (#9710)

Bonus fixes in quota enforcement to use the
new datastructure and use timedValue to cache
a value/reload automatically avoids one less
global variable.

cmd/admin-handlers-users.go

@@ -654,8 +654,8 @@ func (a adminAPIHandlers) AccountUsageInfoHandler(w http.ResponseWriter, r *http
 		if rd || wr {
 			var size uint64
 			// Fetch the data usage of the current bucket
-			if !dataUsageInfo.LastUpdate.IsZero() && len(dataUsageInfo.BucketsSizes) > 0 {
-				size = dataUsageInfo.BucketsSizes[bucket.Name]
+			if !dataUsageInfo.LastUpdate.IsZero() {
+				size = dataUsageInfo.BucketsUsage[bucket.Name].Size
 			}
 			acctInfo.Buckets = append(acctInfo.Buckets, madmin.BucketUsageInfo{
 				Name:    bucket.Name,

cmd/admin-handlers.go

@@ -1329,7 +1329,7 @@ func (a adminAPIHandlers) ServerInfoHandler(w http.ResponseWriter, r *http.Reque
 	dataUsageInfo, err := loadDataUsageFromBackend(ctx, objectAPI)
 	if err == nil {
 		buckets = madmin.Buckets{Count: dataUsageInfo.BucketsCount}
-		objects = madmin.Objects{Count: dataUsageInfo.ObjectsCount}
+		objects = madmin.Objects{Count: dataUsageInfo.ObjectsTotalCount}
 		usage = madmin.Usage{Size: dataUsageInfo.ObjectsTotalSize}
 	}
 

cmd/bucket-quota.go

@@ -20,7 +20,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"sync"
 	"time"
 
 	"github.com/minio/minio/cmd/config"
@@ -31,7 +30,9 @@ import (
 )
 
 // BucketQuotaSys - map of bucket and quota configuration.
-type BucketQuotaSys struct{}
+type BucketQuotaSys struct {
+	bucketStorageCache timedValue
+}
 
 // Get - Get quota configuration.
 func (sys *BucketQuotaSys) Get(bucketName string) (*madmin.BucketQuota, error) {
@@ -63,49 +64,60 @@ func parseBucketQuota(bucket string, data []byte) (quotaCfg *madmin.BucketQuota,
 	return
 }
 
-type bucketStorageCache struct {
-	bucketsSizes map[string]uint64
-	lastUpdate   time.Time
-	mu           sync.Mutex
+func (sys *BucketQuotaSys) check(ctx context.Context, bucket string, size int64) error {
+	objAPI := newObjectLayerWithoutSafeModeFn()
+	if objAPI == nil {
+		return errServerNotInitialized
+	}
+
+	q, err := sys.Get(bucket)
+	if err != nil {
+		return nil
+	}
+
+	if q.Type == madmin.FIFOQuota {
+		return nil
 	}
 
-func (b *bucketStorageCache) check(ctx context.Context, q *madmin.BucketQuota, bucket string, size int64) error {
 	if q.Quota == 0 {
 		// No quota set return quickly.
 		return nil
 	}
 
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	if time.Since(b.lastUpdate) > 10*time.Second {
-		dui, err := loadDataUsageFromBackend(ctx, newObjectLayerWithoutSafeModeFn())
+	sys.bucketStorageCache.Once.Do(func() {
+		sys.bucketStorageCache.TTL = 10 * time.Second
+		sys.bucketStorageCache.Update = func() (interface{}, error) {
+			return loadDataUsageFromBackend(ctx, objAPI)
+		}
+	})
+
+	v, err := sys.bucketStorageCache.Get()
 	if err != nil {
 		return err
 	}
-		b.lastUpdate = time.Now()
-		b.bucketsSizes = dui.BucketsSizes
-	}
-	currUsage := b.bucketsSizes[bucket]
-	if (currUsage + uint64(size)) > q.Quota {
-		return BucketQuotaExceeded{Bucket: bucket}
-	}
+
+	dui := v.(DataUsageInfo)
+
+	bui, ok := dui.BucketsUsage[bucket]
+	if !ok {
+		// bucket not found, cannot enforce quota
+		// call will fail anyways later.
 		return nil
 	}
-func enforceBucketQuota(ctx context.Context, bucket string, size int64) error {
-	if size < 0 {
-		return nil
+
+	if (bui.Size + uint64(size)) > q.Quota {
+		return BucketQuotaExceeded{Bucket: bucket}
 	}
 
-	q, err := globalBucketQuotaSys.Get(bucket)
-	if err != nil {
 	return nil
 }
 
-	if q.Type == madmin.FIFOQuota {
+func enforceBucketQuota(ctx context.Context, bucket string, size int64) error {
+	if size < 0 {
 		return nil
 	}
 
-	return globalBucketStorageCache.check(ctx, q, bucket, size)
+	return globalBucketQuotaSys.check(ctx, bucket, size)
 }
 
 const (
@@ -139,29 +151,40 @@ func enforceFIFOQuota(ctx context.Context, objectAPI ObjectLayer) error {
 	if env.Get(envDataUsageCrawlConf, config.EnableOn) == config.EnableOff {
 		return nil
 	}
+
 	buckets, err := objectAPI.ListBuckets(ctx)
 	if err != nil {
 		return err
 	}
+
+	dataUsageInfo, err := loadDataUsageFromBackend(ctx, objectAPI)
+	if err != nil {
+		return err
+	}
+
 	for _, binfo := range buckets {
 		bucket := binfo.Name
+
+		bui, ok := dataUsageInfo.BucketsUsage[bucket]
+		if !ok {
+			// bucket doesn't exist anymore, or we
+			// do not have any information to proceed.
+			continue
+		}
+
 		// Check if the current bucket has quota restrictions, if not skip it
 		cfg, err := globalBucketQuotaSys.Get(bucket)
 		if err != nil {
 			continue
 		}
+
 		if cfg.Type != madmin.FIFOQuota {
 			continue
 		}
 
-		dataUsageInfo, err := loadDataUsageFromBackend(ctx, objectAPI)
-		if err != nil {
-			return err
-		}
-
 		var toFree uint64
-		if dataUsageInfo.BucketsSizes[bucket] > cfg.Quota && cfg.Quota > 0 {
-			toFree = dataUsageInfo.BucketsSizes[bucket] - cfg.Quota
+		if bui.Size > cfg.Quota && cfg.Quota > 0 {
+			toFree = bui.Size - cfg.Quota
 		}
 
 		if toFree == 0 {
@@ -175,6 +198,7 @@ func enforceFIFOQuota(ctx context.Context, objectAPI ObjectLayer) error {
 		if err := objectAPI.Walk(ctx, bucket, "", objInfoCh); err != nil {
 			return err
 		}
+
 		// reuse the fileScorer used by disk cache to score entries by
 		// ModTime to find the oldest objects in bucket to delete. In
 		// the context of bucket quota enforcement - number of hits are

cmd/data-usage-cache.go

@@ -116,16 +116,16 @@ func (d *dataUsageCache) find(path string) *dataUsageEntry {
 func (d *dataUsageCache) dui(path string, buckets []BucketInfo) DataUsageInfo {
 	e := d.find(path)
 	if e == nil {
-		return DataUsageInfo{LastUpdate: UTCNow()}
+		// No entry found, return empty.
+		return DataUsageInfo{}
 	}
 	flat := d.flatten(*e)
 	return DataUsageInfo{
 		LastUpdate:        d.Info.LastUpdate,
-		ObjectsCount:          flat.Objects,
+		ObjectsTotalCount: flat.Objects,
 		ObjectsTotalSize:  uint64(flat.Size),
-		ObjectsSizesHistogram: flat.ObjSizes.asMap(),
 		BucketsCount:      uint64(len(e.Children)),
-		BucketsSizes:          d.pathSizes(buckets),
+		BucketsUsage:      d.bucketsUsageInfo(buckets),
 	}
 }
 
@@ -232,25 +232,30 @@ func (h *sizeHistogram) add(size int64) {
 	}
 }
 
-// asMap returns the map as a map[string]uint64.
-func (h *sizeHistogram) asMap() map[string]uint64 {
-	res := make(map[string]uint64, 7)
+// toMap returns the map to a map[string]uint64.
+func (h *sizeHistogram) toMap() map[string]uint64 {
+	res := make(map[string]uint64, dataUsageBucketLen)
 	for i, count := range h {
 		res[ObjectsHistogramIntervals[i].name] = count
 	}
 	return res
 }
 
-// pathSizes returns the path sizes as a map.
-func (d *dataUsageCache) pathSizes(buckets []BucketInfo) map[string]uint64 {
-	var dst = make(map[string]uint64, len(buckets))
+// bucketsUsageInfo returns the buckets usage info as a map, with
+// key as bucket name
+func (d *dataUsageCache) bucketsUsageInfo(buckets []BucketInfo) map[string]BucketUsageInfo {
+	var dst = make(map[string]BucketUsageInfo, len(buckets))
 	for _, bucket := range buckets {
 		e := d.find(bucket.Name)
 		if e == nil {
 			continue
 		}
 		flat := d.flatten(*e)
-		dst[bucket.Name] = uint64(flat.Size)
+		dst[bucket.Name] = BucketUsageInfo{
+			Size:                 uint64(flat.Size),
+			ObjectsCount:         uint64(flat.Objects),
+			ObjectSizesHistogram: flat.ObjSizes.toMap(),
+		}
 	}
 	return dst
 }

cmd/data-usage.go

@@ -154,6 +154,22 @@ func loadDataUsageFromBackend(ctx context.Context, objAPI ObjectLayer) (DataUsag
 		return DataUsageInfo{}, err
 	}
 
+	// For forward compatibility reasons, we need to add this code.
+	if len(dataUsageInfo.BucketsUsage) == 0 {
+		dataUsageInfo.BucketsUsage = make(map[string]BucketUsageInfo, len(dataUsageInfo.BucketSizes))
+		for bucket, size := range dataUsageInfo.BucketSizes {
+			dataUsageInfo.BucketsUsage[bucket] = BucketUsageInfo{Size: size}
+		}
+	}
+
+	// For backward compatibility reasons, we need to add this code.
+	if len(dataUsageInfo.BucketSizes) == 0 {
+		dataUsageInfo.BucketSizes = make(map[string]uint64, len(dataUsageInfo.BucketsUsage))
+		for bucket, bui := range dataUsageInfo.BucketsUsage {
+			dataUsageInfo.BucketSizes[bucket] = bui.Size
+		}
+	}
+
 	return dataUsageInfo, nil
 }
 

cmd/globals.go

@@ -215,7 +215,6 @@ var (
 
 	globalBucketObjectLockSys *BucketObjectLockSys
 	globalBucketQuotaSys      *BucketQuotaSys
-	globalBucketStorageCache  bucketStorageCache
 
 	// Disk cache drives
 	globalCacheConfig cache.Config

cmd/metrics.go

@@ -1,5 +1,5 @@
 /*
- * MinIO Cloud Storage, (C) 2018 MinIO, Inc.
+ * MinIO Cloud Storage, (C) 2018-2020 MinIO, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,7 +22,9 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/minio/minio/cmd/config"
 	"github.com/minio/minio/cmd/logger"
+	"github.com/minio/minio/pkg/env"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
@@ -84,6 +86,7 @@ func (c *minioCollector) Collect(ch chan<- prometheus.Metric) {
 	minioVersionInfo.WithLabelValues(Version, CommitID).Set(float64(1.0))
 
 	storageMetricsPrometheus(ch)
+	bucketUsageMetricsPrometheus(ch)
 	networkMetricsPrometheus(ch)
 	httpMetricsPrometheus(ch)
 	cacheMetricsPrometheus(ch)
@@ -345,6 +348,65 @@ func networkMetricsPrometheus(ch chan<- prometheus.Metric) {
 	)
 }
 
+// Populates prometheus with bucket usage metrics, this metrics
+// is only enabled if crawler is enabled.
+func bucketUsageMetricsPrometheus(ch chan<- prometheus.Metric) {
+	objLayer := newObjectLayerWithoutSafeModeFn()
+	// Service not initialized yet
+	if objLayer == nil {
+		return
+	}
+
+	// Crawler disabled, nothing to do.
+	if env.Get(envDataUsageCrawlConf, config.EnableOn) != config.EnableOn {
+		return
+	}
+
+	dataUsageInfo, err := loadDataUsageFromBackend(GlobalContext, objLayer)
+	if err != nil {
+		return
+	}
+
+	// data usage has not captured any data yet.
+	if dataUsageInfo.LastUpdate.IsZero() {
+		return
+	}
+
+	for bucket, usageInfo := range dataUsageInfo.BucketsUsage {
+		// Total space used by bucket
+		ch <- prometheus.MustNewConstMetric(
+			prometheus.NewDesc(
+				prometheus.BuildFQName("bucket", "usage", "size"),
+				"Total bucket size",
+				[]string{"bucket"}, nil),
+			prometheus.GaugeValue,
+			float64(usageInfo.Size),
+			bucket,
+		)
+		ch <- prometheus.MustNewConstMetric(
+			prometheus.NewDesc(
+				prometheus.BuildFQName("bucket", "objects", "count"),
+				"Total number of objects in a bucket",
+				[]string{"bucket"}, nil),
+			prometheus.GaugeValue,
+			float64(usageInfo.ObjectsCount),
+			bucket,
+		)
+		for k, v := range usageInfo.ObjectSizesHistogram {
+			ch <- prometheus.MustNewConstMetric(
+				prometheus.NewDesc(
+					prometheus.BuildFQName("bucket", "objects", "histogram"),
+					"Total number of objects of different sizes in a bucket",
+					[]string{"bucket", "object_size"}, nil),
+				prometheus.GaugeValue,
+				float64(v),
+				bucket,
+				k,
+			)
+		}
+	}
+}
+
 // collects storage metrics for MinIO server in Prometheus specific format
 // and sends to given channel
 func storageMetricsPrometheus(ch chan<- prometheus.Metric) {

cmd/object-api-datatypes.go

@@ -21,6 +21,7 @@ import (
 	"math"
 	"time"
 
+	humanize "github.com/dustin/go-humanize"
 	"github.com/minio/minio/pkg/hash"
 	"github.com/minio/minio/pkg/madmin"
 )
@@ -86,13 +87,23 @@ const (
 // ObjectsHistogramIntervals is the list of all intervals
 // of object sizes to be included in objects histogram.
 var ObjectsHistogramIntervals = []objectHistogramInterval{
-	{"LESS_THAN_1024_B", -1, 1024 - 1},
-	{"BETWEEN_1024_B_AND_1_MB", 1024, 1024*1024 - 1},
-	{"BETWEEN_1_MB_AND_10_MB", 1024 * 1024, 1024*1024*10 - 1},
-	{"BETWEEN_10_MB_AND_64_MB", 1024 * 1024 * 10, 1024*1024*64 - 1},
-	{"BETWEEN_64_MB_AND_128_MB", 1024 * 1024 * 64, 1024*1024*128 - 1},
-	{"BETWEEN_128_MB_AND_512_MB", 1024 * 1024 * 128, 1024*1024*512 - 1},
-	{"GREATER_THAN_512_MB", 1024 * 1024 * 512, math.MaxInt64},
+	{"LESS_THAN_1024_B", 0, humanize.KiByte - 1},
+	{"BETWEEN_1024_B_AND_1_MB", humanize.KiByte, humanize.MiByte - 1},
+	{"BETWEEN_1_MB_AND_10_MB", humanize.MiByte, humanize.MiByte*10 - 1},
+	{"BETWEEN_10_MB_AND_64_MB", humanize.MiByte * 10, humanize.MiByte*64 - 1},
+	{"BETWEEN_64_MB_AND_128_MB", humanize.MiByte * 64, humanize.MiByte*128 - 1},
+	{"BETWEEN_128_MB_AND_512_MB", humanize.MiByte * 128, humanize.MiByte*512 - 1},
+	{"GREATER_THAN_512_MB", humanize.MiByte * 512, math.MaxInt64},
+}
+
+// BucketUsageInfo - bucket usage info provides
+// - total size of the bucket
+// - total objects in a bucket
+// - object size histogram per bucket
+type BucketUsageInfo struct {
+	Size                 uint64            `json:"size"`
+	ObjectsCount         uint64            `json:"objectsCount"`
+	ObjectSizesHistogram map[string]uint64 `json:"objectsSizesHistogram"`
 }
 
 // DataUsageInfo represents data usage stats of the underlying Object API
@@ -101,17 +112,23 @@ type DataUsageInfo struct {
 	// This does not indicate a full scan.
 	LastUpdate time.Time `json:"lastUpdate"`
 
-	ObjectsCount uint64 `json:"objectsCount"`
-	// Objects total size
-	ObjectsTotalSize uint64 `json:"objectsTotalSize"`
+	// Objects total count across all buckets
+	ObjectsTotalCount uint64 `json:"objectsCount"`
 
-	// ObjectsSizesHistogram contains information on objects across all buckets.
-	// See ObjectsHistogramIntervals.
-	ObjectsSizesHistogram map[string]uint64 `json:"objectsSizesHistogram"`
+	// Objects total size across all buckets
+	ObjectsTotalSize uint64 `json:"objectsTotalSize"`
 
+	// Total number of buckets in this cluster
 	BucketsCount uint64 `json:"bucketsCount"`
-	// BucketsSizes is "bucket name" -> size.
-	BucketsSizes map[string]uint64 `json:"bucketsSizes"`
+
+	// Buckets usage info provides following information across all buckets
+	// - total size of the bucket
+	// - total objects in a bucket
+	// - object size histogram per bucket
+	BucketsUsage map[string]BucketUsageInfo `json:"bucketsUsageInfo"`
+
+	// Deprecated kept here for backward compatibility reasons.
+	BucketSizes map[string]uint64 `json:"bucketsSizes"`
 }
 
 // BucketInfo - represents bucket metadata.

docs/metrics/prometheus/README.md

@@ -110,7 +110,7 @@ These are the new set of metrics which will be in effect after `RELEASE.2019-10-
     - Metrics that records the http statistics and latencies are labeled to their respective APIs (putobject,getobject etc).
     - Disk usage metrics are distributed and labeled to the respective disk paths.
 
-For more details, please check the `Migration guide for the new set of metrics`
+For more details, please check the `Migration guide for the new set of metrics`. 
 
 The list of metrics and its definition are as follows. (NOTE: instance here is one MinIO node)
 
@@ -118,42 +118,83 @@ The list of metrics and its definition are as follows. (NOTE: instance here is o
     > 1. Instance here is one MinIO node.
     > 2. `s3 requests` exclude internode requests.
 
-- standard go runtime metrics prefixed by `go_`
-- process level metrics prefixed with `process_`
-- prometheus scrape metrics prefixed with `promhttp_`
-
-- `disk_storage_used` : Disk space used by the disk.
-- `disk_storage_available`: Available disk space left on the disk.
-- `disk_storage_total`: Total disk space on the disk.
-- `minio_disks_offline`: Total number of offline disks in current MinIO instance.
-- `minio_disks_total`: Total number of disks in current MinIO instance.
-- `s3_requests_total`: Total number of s3 requests in current MinIO instance.
-- `s3_errors_total`: Total number of errors in s3 requests in current MinIO instance.
-- `s3_requests_current`: Total number of active s3 requests in current MinIO instance.
-- `internode_rx_bytes_total`: Total number of internode bytes received by current MinIO server instance.
-- `internode_tx_bytes_total`: Total number of bytes sent to the other nodes by current MinIO server instance.
-- `s3_rx_bytes_total`: Total number of s3 bytes received by current MinIO server instance.
-- `s3_tx_bytes_total`: Total number of s3 bytes sent by current MinIO server instance.
-- `minio_version_info`: Current MinIO version with commit-id.
-- `s3_ttfb_seconds`: Histogram that holds the latency information of the requests.
+### Default set of information
+| name        | description                     |
+|:------------|:--------------------------------|
+| `go_`       | all standard go runtime metrics |
+| `process_`  | all process level metrics       |
+| `promhttp_` | all prometheus scrape metrics   |
+
+### MinIO node specific information
+| name                       | description                                                                    |
+|:---------------------------|:-------------------------------------------------------------------------------|
+| `minio_version_info`       | Current MinIO version with its commit-id                                       |
+| `minio_disks_offline`      | Total number of offline disks on current MinIO instance                        |
+| `minio_disks_total`        | Total number of disks on current MinIO instance                                |
+
+### Disk metrics are labeled by 'disk' which indentifies each disk
+| name                       | description                                                                    |
+|:---------------------------|:-------------------------------------------------------------------------------|
+| `disk_storage_total`       | Total size of the disk                                                         |
+| `disk_storage_used`        | Total disk space used per disk                                                 |
+| `disk_storage_available`   | Total available disk space per disk                                            |
+
+### S3 API metrics are labeled by 'api' which identifies different S3 API requests
+| name                       | description                                                                    |
+|:---------------------------|:-------------------------------------------------------------------------------|
+| `s3_requests_total`        | Total number of s3 requests in current MinIO instance                          |
+| `s3_errors_total`          | Total number of errors in s3 requests in current MinIO instance                |
+| `s3_requests_current`      | Total number of active s3 requests in current MinIO instance                   |
+| `s3_rx_bytes_total`        | Total number of s3 bytes received by current MinIO server instance             |
+| `s3_tx_bytes_total`        | Total number of s3 bytes sent by current MinIO server instance                 |
+| `s3_ttfb_seconds`          | Histogram that holds the latency information of the requests                   |
+
+#### Internode metrics only available in a distributed setup
+| name                       | description                                                                    |
+|:---------------------------|:-------------------------------------------------------------------------------|
+| `internode_rx_bytes_total` | Total number of internode bytes received by current MinIO server instance      |
+| `internode_tx_bytes_total` | Total number of bytes sent to the other nodes by current MinIO server instance |
 
 Apart from above metrics, MinIO also exposes below mode specific metrics
 
+### Bucket usage specific metrics
+All metrics are labeled by `bucket`, each metric is displayed per bucket. `buckets_objects_histogram` is additionally labeled by `object_size` string which is represented by any of the following values
+
+- *LESS_THAN_1024_B*
+- *BETWEEN_1024_B_AND_1_MB*
+- *BETWEEN_1_MB_AND_10_MB*
+- *BETWEEN_10_MB_AND_64_MB*
+- *BETWEEN_64_MB_AND_128_MB*
+- *BETWEEN_128_MB_AND_512_MB*
+- *GREATER_THAN_512_MB*
+
+| name                       | description                                         |
+|:---------------------------|:----------------------------------------------------|
+| `bucket_usage_size`        | Total size of the bucket                            |
+| `bucket_objects_count`     | Total number of objects in a bucket                 |
+| `bucket_objects_histogram` | Total number of objects filtered by different sizes |
+
 ### Cache specific metrics
 
 MinIO Gateway instances enabled with Disk-Caching expose caching related metrics.
 
-- `cache_data_served`: Total number of bytes served from cache.
-- `cache_hits_total`: Total number of cache hits.
-- `cache_misses_total`: Total number of cache misses.
+| name                 | description                             |
+|:---------------------|:----------------------------------------|
+| `cache_data_served`  | Total number of bytes served from cache |
+| `cache_hits_total`   | Total number of cache hits              |
+| `cache_misses_total` | Total number of cache misses            |
 
 ### Gateway & Cache specific metrics
 
 MinIO Gateway instance exposes metrics related to Gateway communication with the cloud backend (S3, Azure & GCS Gateway).
 
-- `gateway_<gateway_type>_requests`: Total number of requests made to cloud backend. This metrics has a label `method` that identifies GET, HEAD, PUT and POST Requests.
-- `gateway_<gateway_type>_bytes_sent`: Total number of bytes sent to cloud backend (in PUT & POST Requests).
-- `gateway_<gateway_type>_bytes_received`: Total number of bytes received from cloud backend (in GET & HEAD Requests).
+`<gateway_type>` changes based on the gateway in use can be 's3', 'gcs' or 'azure'. Other metrics are labeled with `method` that identifies HTTP GET, HEAD, PUT and POST requests to the backend.
+
+| name                                    | description                                                                |
+|:----------------------------------------|:---------------------------------------------------------------------------|
+| `gateway_<gateway_type>_requests`       | Total number of requests made to the gateway backend                       |
+| `gateway_<gateway_type>_bytes_sent`     | Total number of bytes sent to cloud backend (in PUT & POST Requests)       |
+| `gateway_<gateway_type>_bytes_received` | Total number of bytes received from cloud backend (in GET & HEAD Requests) |
 
 Note that this is currently only support for Azure, S3 and GCS Gateway.
 
@@ -161,10 +202,12 @@ Note that this is currently only support for Azure, S3 and GCS Gateway.
 
 MinIO exposes self-healing related metrics for erasure-code deployments _only_. These metrics are _not_ available on Gateway or Single Node, Single Drive deployments. Note that these metrics will be exposed _only_ when there is a relevant event happening on MinIO server.
 
-- `self_heal_time_since_last_activity`: Time elapsed since last self-healing related activity.
-- `self_heal_objects_scanned`: Number of objects scanned by self-healing thread in its current run. This will reset when a fresh self-healing run starts. This is labeled with the object type scanned.
-- `self_heal_objects_healed`: Number of objects healing by self-healing thread in its current run. This will reset when a fresh self-healing run starts. This is labeled with the object type scanned.
-- `self_heal_objects_heal_failed`: Number of objects for which self-healing failed in its current run. This will reset when a fresh self-healing run starts. This is labeled with disk status and its endpoint.
+| name                                 | description                                                                                                                                                                 |
+|:-------------------------------------|:----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `self_heal_time_since_last_activity` | Time elapsed since last self-healing related activity                                                                                                                       |
+| `self_heal_objects_scanned`          | Number of objects scanned by self-healing thread in its current run. This will reset when a fresh self-healing run starts. This is labeled with the object type scanned     |
+| `self_heal_objects_healed`           | Number of objects healing by self-healing thread in its current run. This will reset when a fresh self-healing run starts. This is labeled with the object type scanned     |
+| `self_heal_objects_heal_failed`      | Number of objects for which self-healing failed in its current run. This will reset when a fresh self-healing run starts. This is labeled with disk status and its endpoint |
 
 ## Migration guide for the new set of metrics