sync.RWMutex                 // mutex for Cache
	mostRecentStatsMu sync.Mutex // mutex for mostRecentStats

	wlock sync.RWMutex // mutex for active workers

	movingAvgTicker *time.Ticker // Ticker for calculating moving averages
	wTimer          *time.Ticker // ticker for calculating active workers
	qTimer          *time.Ticker // ticker for calculating queue stats
}

func (r *ReplicationStats) trackEWMA() {
	for {
		select {

	Rotational bool
	Metrics    DiskMetrics
	Error      string // carries the error over the network
}

// DiskMetrics has the information about XL Storage APIs
// the number of calls of each API and the moving average of
// the duration of each API.
type DiskMetrics struct {
	LastMinute              map[string]AccElem `json:"apiLatencies,omitempty"`
	APICalls                map[string]uint64  `json:"apiCalls,omitempty"`

		var hint string
		if endpoint.URL != nil {
			hint = fmt.Sprintf("Drive '%s' does not support O_DIRECT flags, MinIO erasure coding requires filesystems with O_DIRECT support", endpoint.Path)
		} else {
			hint = "Drives do not support O_DIRECT flags, MinIO erasure coding requires filesystems with O_DIRECT support"
		}
		logger.Fatal(config.ErrUnsupportedBackend(err).Hint(hint), "Unable to initialize backend")

		isDecommissioned := z.poolMeta.isBucketDecommissioned(idx, bucket.String())
		z.poolMetaMutex.RUnlock()
		if isDecommissioned {
			if serverDebugLog {
				console.Debugln("decommission: already done, moving on", bucket)
			}

			z.poolMetaMutex.Lock()
			if z.poolMeta.BucketDone(idx, bucket) {
				// remove from pendingBuckets and persist.
				decomLogIf(ctx, z.poolMeta.save(ctx, z.serverPools))
			}

			}
			sys.updateBandwidthLimit(bucket, tgt.Arn, tgt.BandwidthLimit)
		}

		if !tgts.Empty() {
			sys.targetsMap[bucket] = tgts.Targets
		}
	}
}

// create minio-go clients for buckets having remote targets
func (sys *BucketTargetSys) set(bucket BucketInfo, meta BucketMetadata) {
	cfg := meta.bucketTargetConfig
	if cfg == nil || cfg.Empty() {
		return
	}
	sys.Lock()
	defer sys.Unlock()

	p.diskID.Store(&id)
}

func (p *xlStorageDiskIDCheck) checkDiskStale() error {
	if *p.diskID.Load() == emptyDiskID {
		// For empty disk-id we allow the call as the server might be
		// coming up and trying to read format.json or create format.json
		return nil
	}
	storedDiskID, err := p.storage.GetDiskID()
	if err != nil {
		// return any error generated while reading `format.json`
		return err
	}

}

// exponentialMovingAverage calculates the exponential moving average
func exponentialMovingAverage(beta, previousAvg, incrementAvg float64) float64 {
	return (1-beta)*incrementAvg + beta*previousAvg
}

// getExpMovingAvgBytesPerSecond returns the exponential moving average for the bucket/target in bytes
func (m *rateMeasurement) getExpMovingAvgBytesPerSecond() float64 {
	m.lock.Lock()

	}
	result = totalSizes[0]
	for i := 1; i < len(totalSizes); i++ {
		result = gcd(result, totalSizes[i])
	}
	return result
}

// isValidSetSize - checks whether given count is a valid set size for erasure coding.
var isValidSetSize = func(count uint64) bool {
	return (count >= setSizes[0] && count <= setSizes[len(setSizes)-1])
}

func commonSetDriveCount(divisibleSize uint64, setCounts []uint64) (setSize uint64) {

//     token: "Bearer xxxxx" # optional authentication token for the notification endpoint

//   retry:
//     attempts: 10 # number of retries for the job before giving up
//     delay: "500ms" # least amount of delay between each retry

//go:generate msgp -file $GOFILE -unexported

// BatchKeyRotationType defines key rotation type
type BatchKeyRotationType string

const (

}

// IsValid - tells if erasure info fields are valid.
func (fi FileInfo) IsValid() bool {
	if fi.Deleted {
		// Delete marker has no data, no need to check
		// for erasure coding information
		return true
	}
	dataBlocks := fi.Erasure.DataBlocks
	parityBlocks := fi.Erasure.ParityBlocks
	correctIndexes := (fi.Erasure.Index > 0 &&
		fi.Erasure.Index <= dataBlocks+parityBlocks &&