err := srv.listener.Close()
	srv.listenerMutex.Unlock()
	if err != nil {
		return err
	}

	pollIntervalBase := time.Millisecond
	nextPollInterval := func() time.Duration {
		// Add 10% jitter.
		interval := pollIntervalBase + time.Duration(rand.Intn(int(pollIntervalBase/10)))
		// Double and clamp for next time.
		pollIntervalBase *= 2
		if pollIntervalBase > shutdownPollIntervalMax {

			return '0'
		case r == '_', r == '$':
			return r
		default:
			valid = false
			return -1
		}
	}, name)

	if valid {
		// check for simple name or quoted name
		// - letter/underscore followed by one or more letter/digit/underscore
		// - any text between quotes (text cannot contain a quote itself)
		if match, err := regexp.MatchString("^[a_][a0_$]*$", cleaned); err != nil {
			return err
		} else if match {

# How to monitor MinIO server with Grafana [![Slack](https://slack.min.io/slack?type=svg)](https://slack.min.io)

[Grafana](https://grafana.com/) allows you to query, visualize, alert on and understand your metrics no matter where they are stored. Create, explore, and share dashboards with your team and foster a data driven culture.

## Prerequisites

			}
			z.poolMetaMutex.Unlock()
		}

		wk.Take()
		go func(setIdx int) {
			defer wk.Give()
			// We will perpetually retry listing if it fails, since we cannot
			// possibly give up in this matter
			for {
				if contextCanceled(ctx) {
					break
				}

				err := set.listObjectsToDecommission(ctx, bi,
					func(entry metaCacheEntry) {
						wk.Take()
						go decommissionEntry(entry)

					// Break out on errors.
					sendResult()
					return
				}
			}

			sendResult()
			if !opts.autotune {
				break
			}

			// Try with a higher concurrency to see if we get better throughput
			concurrency += (concurrency + 1) / 2
		}
	}()
	return ch
}

func driveSpeedTest(ctx context.Context, opts madmin.DriveSpeedTestOpts) madmin.DriveSpeedTestResult {
	perf := &dperf.DrivePerf{

						return err
					}
				}
				versions = append(versions, xl2.versions)
			}

			if xl != nil && len(versions) > 0 {
				// Merge all versions. 'strict' doesn't matter since we only need one.
				xl.versions = mergeXLV2Versions(readQuorum, true, 0, versions...)
				if meta, err := xl.AppendTo(metaDataPoolGet()); err == nil {
					if best.reusable {
						metaDataPoolPut(best.metadata)

## Request, System and Cluster Metrics

At a high level metrics are grouped into three categories, listed in the following sub-sections. The path in each of the tables is relative to the top-level endpoint.

)

const letterBytes = "abcdefghijklmnopqrstuvwxyz01234569"
const (
	letterIdxBits = 6                    // 6 bits to represent a letter index
	letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
	letterIdxMax  = 63 / letterIdxBits   // # of letter indices fitting in 63 bits
)

// Random number state.
// We generate random temporary file names so that there's a good

type ARN struct {
	Partition    string
	Service      string
	Region       string
	ResourceType string
	ResourceID   string
}

// Allows english letters, numbers, '.', '-', '_' and '/'. Starts with a
// letter or digit. At least 1 character long.
var validResourceIDRegex = regexp.MustCompile(`[A-Za-z0-9_/\.-]+$`)

// NewIAMRoleARN - returns an ARN for a role in MinIO.
func NewIAMRoleARN(resourceID, serverRegion string) (ARN, error) {

	bucketResults := make(chan dataUsageEntryInfo, len(disks))

	// Start async collector/saver.
	// This goroutine owns the cache.
	var saverWg sync.WaitGroup
	saverWg.Add(1)
	go func() {
		// Add jitter to the update time so multiple sets don't sync up.
		updateTime := 30*time.Second + time.Duration(float64(10*time.Second)*rand.Float64())
		t := time.NewTicker(updateTime)
		defer t.Stop()
		defer saverWg.Done()