// If the channel reaches above half capacity
		// we spawn more workers. The workers spawned
		// from this main worker routine will exit
		// once the channel drops below half capacity
		// and when it's been at least 30 seconds since
		// we launched a new worker.
		if mainWorker && len(h.logCh) > cap(h.logCh)/2 {
			nWorkers := atomic.LoadInt64(&h.workers)
			if nWorkers < h.maxWorkers {

// newBatchJobPool creates a pool of job manifest workers of specified size
func newBatchJobPool(ctx context.Context, o ObjectLayer, workers int) *BatchJobPool {
	jpool := &BatchJobPool{
		ctx:          ctx,
		objLayer:     o,
		jobCh:        make(chan *BatchJobRequest, 10000),
		workerKillCh: make(chan struct{}, workers),
		jobCancelers: make(map[string]context.CancelFunc),
	}

}

// ActiveWorkerStat is stat for active replication workers
type ActiveWorkerStat struct {
	Curr int     `json:"curr"`
	Avg  float32 `json:"avg"`
	Max  int     `json:"max"`
	hist metrics.Histogram
}

func newActiveWorkerStat(r metrics.Registry) *ActiveWorkerStat {
	h := metrics.NewHistogram(metrics.NewUniformSample(100))
	r.Register("replication.active_workers", h)
	return &ActiveWorkerStat{
		hist: h,
	}
}

	if source.noWait {
		select {
		case globalBackgroundHealRoutine.tasks <- task:
			if serverDebugLog {
				fmt.Printf("Task in the queue: %#v\n", task)
			}
		default:
			// task queue is full, no more workers, we shall move on and heal later.
			return nil
		}
		// Don't wait for result
		return nil
	}

	// respCh must be set to wait for result.
	// We make it size 1, so a result can always be written

	current     []jstream.KVS   // current block of results to be returned
	recordsRead int             // number of records read in current slice
	input       chan *queueItem // input for workers
	queue       chan *queueItem // output from workers in order
	err         error           // global error state, only touched by Reader.Read
	bufferPool  sync.Pool       // pool of []byte objects for input

			Description: "manage namespace scanning for usage calculation, lifecycle, healing and more",
		},
		config.HelpKV{
			Key:         config.BatchSubSys,
			Description: "manage batch job workers and wait times",
		},
		config.HelpKV{
			Key:         config.CompressionSubSys,
			Description: "enable server side compression of objects",
		},
		config.HelpKV{

	if v := globalHealConfig.GetWorkers(); v > 0 {
		numHealers = uint64(v)
	}

	healingLogEvent(ctx, fmt.Sprintf("Healing drive '%s' - use %d parallel workers.", tracker.disk.String(), numHealers))

	jt, _ := workers.New(int(numHealers))

	var retErr error
	// Heal all buckets with all objects
	for _, bucket := range healBuckets {
		if tracker.isHealed(bucket) {
			continue
		}

	}
	t.replicationPriority = cfg.ReplicationPriority
	t.replicationMaxWorkers = cfg.ReplicationMaxWorkers

	// N B api.transition_workers will be deprecated
	if globalTransitionState != nil {
		globalTransitionState.UpdateWorkers(cfg.TransitionWorkers)
	}
	t.transitionWorkers = cfg.TransitionWorkers

	t.staleUploadsExpiry = cfg.StaleUploadsExpiry

var renamedSubsys = map[string]string{
	CrawlerSubSys: ScannerSubSys,
	// Add future sub-system renames
}

const ( // deprecated keys
	apiReplicationWorkers       = "replication_workers"
	apiReplicationFailedWorkers = "replication_failed_workers"
)

// map of subsystem to deleted keys
var deletedSubSysKeys = map[string][]string{
	APISubSys: {apiReplicationWorkers, apiReplicationFailedWorkers},

// volume, path and operation ID.
func (n *nsLockMap) NewNSLock(lockers func() ([]dsync.NetLocker, string), volume string, paths ...string) RWLocker {
	opsID := mustGetUUID()
	if n.isDistErasure {
		drwmutex := dsync.NewDRWMutex(&dsync.Dsync{
			GetLockers: lockers,
			Timeouts:   dsync.DefaultTimeouts,
		}, pathsJoinPrefix(volume, paths...)...)