globalNetPerfMinDuration     = time.Second * 10
	globalNetPerfRX              netPerfRX
	globalSiteNetPerfRX          netPerfRX
	globalObjectPerfBucket       = "minio-perf-test-tmp-bucket"
	globalObjectPerfUserMetadata = "X-Amz-Meta-Minio-Object-Perf" // Clients can set this to bypass S3 API service freeze. Used by object pref tests.

	// MinIO version unix timestamp
	globalVersionUnix uint64

	// MinIO client

// flags and shouldn't be considered as replacement
// for os.OpenFile().
func LockedOpenFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {
	return lockedOpenFile(path, flag, perm, 0)
}

// Open - Call os.OpenFile
func Open(path string, flag int, perm os.FileMode) (*os.File, error) {
	return os.OpenFile(path, flag, perm)

}

// OpenFile captures time taken to call os.OpenFile
func OpenFile(name string, flag int, perm os.FileMode) (f *os.File, err error) {
	switch flag & writeMode {
	case writeMode:
		defer updateOSMetrics(osMetricOpenFileW, name)(err)
	default:
		defer updateOSMetrics(osMetricOpenFileR, name)(err)
	}
	return os.OpenFile(name, flag, perm)
}

// Access captures time taken to call syscall.Access()

				// proxy to replication target if active-active replication is in place.
				reader, proxy, perr = proxyGetToReplicationTarget(ctx, bucket, object, rs, r.Header, opts, proxytgts)
				if perr != nil {
					globalReplicationStats.incProxy(bucket, getObjectAPI, true)
					proxyGetErr := ErrorRespToObjectError(perr, bucket, object)

)

func (er erasureObjects) getOnlineDisks() (newDisks []StorageAPI) {
	disks := er.getDisks()
	var wg sync.WaitGroup
	var mu sync.Mutex
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	for _, i := range r.Perm(len(disks)) {
		i := i
		wg.Add(1)
		go func() {
			defer wg.Done()
			if disks[i] == nil {
				return
			}
			di, err := disks[i].DiskInfo(context.Background(), DiskInfoOptions{})

// ODirectPlatform indicates if the platform supports O_DIRECT
const ODirectPlatform = true

// OpenFileDirectIO - bypass kernel cache.
func OpenFileDirectIO(filePath string, flag int, perm os.FileMode) (*os.File, error) {
	return directio.OpenFile(filePath, flag, perm)
}

// DisableDirectIO - disables directio mode.
func DisableDirectIO(f *os.File) error {
	fd := f.Fd()
	flag, err := unix.FcntlInt(fd, unix.F_GETFL, 0)
	if err != nil {

drives, some applications with high concurrency might require MinIO cluster to be tuned such that to avoid random I/O on the drives. The way to convert high concurrent I/O into a sequential I/O is by reducing the number of concurrent operations allowed per cluster. This allows MinIO cluster to be operationally resilient to such workloads, while also making sure the drives are at optimal efficiency and responsive.

Example: Limit a MinIO cluster to accept at max 1600 simultaneous S3 API requests...

package cmd

import (
	"context"
)

const (
	memTotal     = "total"
	memUsed      = "used"
	memFree      = "free"
	memBuffers   = "buffers"
	memCache     = "cache"
	memUsedPerc  = "used_perc"
	memShared    = "shared"
	memAvailable = "available"
)

var (
	memTotalMD     = NewGaugeMD(memTotal, "Total memory on the node")
	memUsedMD      = NewGaugeMD(memUsed, "Used memory on the node")

# Patterns to ignore when building packages.
# This supports shell glob matching, relative path matching, and
# negation (prefixed with !). Only one pattern per line.
.DS_Store
# Common VCS dirs
.git/
.gitignore
.bzr/
.bzrignore
.hg/
.hgignore
.svn/
# Common backup files
*.swp
*.bak
*.tmp
*~
# Various IDEs
.project
.idea/
*.tmproj
# OWNERS file for Kubernetes

  metrics_path: /minio/v2/metrics/bucket
  scheme: http
  static_configs:
  - targets: ['localhost:9000']
```

##### Node (optional)

Optionally you can also collect per node metrics. This needs to be done on a per server instance.
The scrape configurations should use all the servers under `targets` so that graphing systems like
grafana can visualize them for all the nodes

```yaml
scrape_configs: