### Sync/Async Replication

By default, replication is completed asynchronously. If synchronous replication is desired, set the --sync flag while adding a
remote replication target using the `mc admin bucket remote add` command. For mc releases on or after `RELEASE.2022-12-24T15-21-38Z`, the 

			objInfo := fi.ToObjectInfo(bucket, object, versioned)

			evt := evalActionFromLifecycle(ctx, *lc, lr, rcfg, objInfo)
			switch {
			case evt.Action.DeleteRestored(): // if restored copy has expired, delete it synchronously
				applyExpiryOnTransitionedObject(ctx, z, objInfo, evt, lcEventSrc_Decom)
				return false
			case evt.Action.Delete():
				globalExpiryState.enqueueByDays(objInfo, evt, lcEventSrc_Decom)
				return true

	}

	// Empty fi.VersionID indicates that versioning is either
	// suspended or disabled on this bucket. RenameData will replace
	// the 'null' version. We add a free-version to track its tiered
	// content for asynchronous deletion.
	//
	// Note: RestoreObject and HealObject requests don't end up replacing the
	// null version and therefore don't require the free-version to track
	// anything

// deleted/overwritten version. This version is visible _only_to the scanner routine, for subsequent deletion.
// This kind of tracking is necessary since a version's tiered content is deleted asynchronously.

// Backend directory tree structure:
// disk1/
// └── bucket
//     └── object
//         ├── a192c1d5-9bd5-41fd-9a90-ab10e165398d
//         │   └── part.1

```
cat ${HADOOP_CONF_DIR}/core-site.xml | kv-pairify | grep "mapred"

mapred.maxthreads.generate.mapoutput=2 # Num threads to write map outputs
mapred.maxthreads.partition.closer=0 # Asynchronous map flushers
mapreduce.fileoutputcommitter.algorithm.version=2 # Use the latest committer version
mapreduce.job.reduce.slowstart.completedmaps=0.99 # 99% map, then reduce

		}
	}

	for i, version := range x.versions {
		if version.header.VersionID != uv || version.header.Type != ObjectType {
			continue
		}
		// if uv has tiered content we add a
		// free-version to track it for asynchronous
		// deletion via scanner.
		ver, err := x.getIdx(i)
		if err != nil {
			return err
		}

		if freeVersion, toFree := ver.ObjectV2.InitFreeVersion(fi); toFree {
			return x.addVersion(freeVersion)

	targetIDSet := evnot.bucketRulesMap[args.BucketName].Match(args.EventName, args.Object.Name)
	evnot.RUnlock()

	if len(targetIDSet) == 0 {
		return
	}

	// If MINIO_API_SYNC_EVENTS is set, send events synchronously.
	evnot.targetList.Send(args.ToEvent(true), targetIDSet, globalAPIConfig.isSyncEventsEnabled())
}

type eventArgs struct {
	EventName    event.Name
	BucketName   string
	Object       ObjectInfo

			objInfo := fi.ToObjectInfo(bucket, object, versioned)

			evt := evalActionFromLifecycle(ctx, *lc, lr, rcfg, objInfo)
			switch {
			case evt.Action.DeleteRestored(): // if restored copy has expired,delete it synchronously
				applyExpiryOnTransitionedObject(ctx, newObjectLayerFn(), objInfo, evt, lcEventSrc_Heal)
				return false
			case evt.Action.Delete():
				globalExpiryState.enqueueByDays(objInfo, evt, lcEventSrc_Heal)

			Optional:    true,
			Type:        "on|off",
		},
		config.HelpKV{
			Key:         target.NATSStreamingAsync,
			Description: "[DEPRECATED] set to 'on', to enable asynchronous publish",
			Optional:    true,
			Type:        "on|off",
		},
		config.HelpKV{
			Key:         target.NATSStreamingMaxPubAcksInFlight,

streaming                         (on|off)    set to 'on', to use streaming NATS server
streaming_async                   (on|off)    set to 'on', to enable asynchronous publish
streaming_max_pub_acks_in_flight  (number)    number of messages to publish without waiting for ACKs
streaming_cluster_id              (string)    unique ID for NATS streaming cluster