}

// Stat captures time taken to call os.Stat
func Stat(name string) (info os.FileInfo, err error) {
	defer updateOSMetrics(osMetricStat, name)(err)
	return os.Stat(name)
}

// Create captures time taken to call os.Create
func Create(name string) (f *os.File, err error) {
	defer updateOSMetrics(osMetricCreate, name)(err)
	return os.Create(name)
}

// Fdatasync captures time taken to call Fdatasync

		prometheus.HistogramOpts{
			Name:    "s3_ttfb_seconds",
			Help:    "Time taken by requests served by current MinIO server instance",
			Buckets: []float64{.05, .1, .25, .5, 1, 2.5, 5, 10},
		},
		[]string{"api"},
	)
	bucketHTTPRequestsDuration = prometheus.NewHistogramVec(
		prometheus.HistogramOpts{
			Name:    "s3_ttfb_seconds",
			Help:    "Time taken by requests served by current MinIO server instance per bucket",

}

// Health - returns current status of the object layer health,
// provides if write access exists across sets, additionally
// can be used to query scenarios if health may be lost
// if this node is taken down by an external orchestrator.
func (z *erasureServerPools) Health(ctx context.Context, opts HealthOptions) HealthResult {
	reqInfo := (&logger.ReqInfo{}).AppendTags("maintenance", strconv.FormatBool(opts.Maintenance))

X-Xss-Protection: 1; mode=block
Date: Tue, 21 Jul 2020 00:36:14 GMT
```

### Checking cluster health for maintenance

You may query the cluster probe endpoint to check if the node which received the request can be taken down for maintenance, if the server replies back '412 Precondition Failed' this means you will lose HA. '200 OK' means you are okay to proceed.

```
curl http://minio1:9001/minio/health/cluster?maintenance=true

	requestsCount: make(map[string]struct {
		success int64
		failure int64
	}),
	histogram: prometheus.NewHistogramVec(prometheus.HistogramOpts{
		Name:    "tier_ttlb_seconds",
		Help:    "Time taken by requests served by warm tier",
		Buckets: []float64{0.01, 0.1, 1, 2, 5, 10, 60, 5 * 60, 15 * 60, 30 * 60},
	}, []string{"tier"}),
}

func (t *tierMetrics) Observe(tier string, dur time.Duration) {

		scred := su.Credentials
		if scred.ParentUser != parentUser {
			return updatedAt, fmt.Errorf("%w: the service account access key is taken by another user", errIAMServiceAccountNotAllowed)
		}
		return updatedAt, fmt.Errorf("%w: the service account access key already taken", errIAMServiceAccountNotAllowed)
	}

	// Parent user must not be a service account.

## Healthcheck Probe

MinIO server has two healthcheck related un-authenticated endpoints, a liveness probe to indicate if server is responding, cluster probe to check if server can be taken down for maintenance.

- Liveness probe available at `/minio/health/live`
- Cluster probe available at `/minio/health/cluster`

	labels := []string{"GetObject", "PutObject", "CopyObject", "CompleteMultipartUpload"}
	ttfbHist := prometheus.NewHistogramVec(
		prometheus.HistogramOpts{
			Name:    "s3_ttfb_seconds",
			Help:    "Time taken by requests served by current MinIO server instance",
			Buckets: histBuckets,
		},
		[]string{"api"},
	)
	observations := []struct {
		val   float64
		label string
	}{
		{
			val:   0.02,

	if result.HealingDrives > 0 {
		w.Header().Set(xhttp.MinIOHealingDrives, strconv.Itoa(result.HealingDrives))
	}
	if !result.Healthy {
		// As a maintenance call we are purposefully asked to be taken
		// down, this is for orchestrators to know if we can safely
		// take this server down, return appropriate error.
		if opts.Maintenance {
			writeResponse(w, http.StatusPreconditionFailed, nil, mimeNone)
		} else {

	}

	l.mutex.Lock()
	defer l.mutex.Unlock()

	if !l.canTakeLock(args.Resources...) {
		// Not all locks can be taken on resources,
		// reject it completely.
		return false, nil
	}

	// No locks held on the all resources, so claim write
	// lock on all resources at once.
	for i, resource := range args.Resources {