ttfbDistribution    = "seconds_distribution"
	ttlbDistribution    = "ttlb_seconds_distribution"

	lastActivityTime = "last_activity_nano_seconds"
	startTime        = "starttime_seconds"
	upTime           = "uptime_seconds"
	memory           = "resident_memory_bytes"
	vmemory          = "virtual_memory_bytes"
	cpu              = "cpu_total_seconds"

| `start_time_seconds`          | `gauge`   | Start time for MinIO process in seconds since Unix epoc                                                        | `server` |
| `uptime_seconds`              | `gauge`   | Uptime for MinIO process in seconds                                                                            | `server` |

| `minio_cluster_replication_link_offline_duration_seconds`  | Total duration of replication link being offline in seconds since last offline event                     |
| `minio_cluster_replication_link_downtime_duration_seconds` | Total downtime of replication link in seconds since server start                                         |

	var (
		// We check every 15 seconds if the disk is writable and we can read back.
		checkEvery = 15 * time.Second

		// If the disk has completed an operation successfully within last 5 seconds, don't check it.
		skipIfSuccessBefore = 5 * time.Second
	)

	// if disk max timeout is smaller than checkEvery window
	// reduce checks by a second.
	if globalDriveConfig.GetMaxTimeout() <= checkEvery {

		memCache:          "Cache memory on the node",
		memAvailable:      "Available memory on the node",
		readsPerSec:       "Reads per second on a drive",
		writesPerSec:      "Writes per second on a drive",
		readsKBPerSec:     "Kilobytes read per second on a drive",
		writesKBPerSec:    "Kilobytes written per second on a drive",
		readsAwait:        "Average time for read requests to be served on a drive",

		TotalTicks:   currentStats.TotalTicks - initialStats.TotalTicks,
	}
}

func getDriveIOStatMetrics(ioStats madmin.DiskIOStats, duration time.Duration) (m driveIOStatMetrics) {
	durationSecs := duration.Seconds()

	m.readsPerSec = float64(ioStats.ReadIOs) / durationSecs
	m.readsKBPerSec = float64(ioStats.ReadSectors) * float64(sectorSize) / kib / durationSecs
	if ioStats.ReadIOs > 0 {

	if result.Error != nil {
		return RemoteTargetConnectionErr{Bucket: tgt.TargetBucket, Err: result.Error, AccessKey: tgt.Credentials.AccessKey}
	}
	if !result.Online {
		err := errors.New("Health check timed out after 3 seconds")
		return RemoteTargetConnectionErr{Err: err}
	}

	sys.Lock()
	defer sys.Unlock()

	tgts := sys.targetsMap[bucket]
	newtgts := make([]madmin.BucketTarget, len(tgts))
	found := false

	processCPUTotalSeconds          = "cpu_total_seconds"
	processGoRoutineTotal           = "go_routine_total"
	processIORCharBytes             = "io_rchar_bytes"
	processIOReadBytes              = "io_read_bytes"
	processIOWCharBytes             = "io_wchar_bytes"
	processIOWriteBytes             = "io_write_bytes"
	processStartTimeSeconds         = "start_time_seconds"
	processUptimeSeconds            = "uptime_seconds"

	pluginAuthnServiceFailedRequestsMinute = "plugin_authn_service_failed_requests_minute"
	pluginAuthnServiceLastFailSeconds      = "plugin_authn_service_last_fail_seconds"
	pluginAuthnServiceLastSuccSeconds      = "plugin_authn_service_last_succ_seconds"
	pluginAuthnServiceSuccAvgRttMsMinute   = "plugin_authn_service_succ_avg_rtt_ms_minute"
	pluginAuthnServiceSuccMaxRttMsMinute   = "plugin_authn_service_succ_max_rtt_ms_minute"

// to fail with a ten seconds timeout, returning nil.
func getClusterMetaInfo(ctx context.Context) []byte {
	objectAPI := newObjectLayerFn()
	if objectAPI == nil {
		return nil
	}

	// Add a ten seconds timeout because getting profiling data
	// is critical for debugging, in contrary to getting cluster info
	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
	defer cancel()