// Deleted Buckets prefix.
	deletedBucketsPrefix = ".deleted"

	// ETag (hex encoded md5sum) of empty string.
	emptyETag = "d41d8cd98f00b204e9800998ecf8427e"
)

// Global object layer mutex, used for safely updating object layer.
var globalObjLayerMutex sync.RWMutex

// Global object layer, only accessed by globalObjectAPI.
var globalObjectAPI ObjectLayer

type storageOpts struct {
	cleanUp     bool
	healthCheck bool
}

	if t.opts.NoWait && v != nil && tNow-vTime < ttl.Milliseconds()*2 && (v.e == nil || t.opts.CacheError) {
		if t.updating.TryLock() {
			go func() {
				defer t.updating.Unlock()
				t.update()
			}()
		}
		return v.v, v.e
	}

	// Get lock. Either we get it or we wait for it.
	t.updating.Lock()
	if time.Since(time.UnixMilli(t.lastUpdateMs.Load())) < ttl {
		// There is a new value, release lock and return it.

		queued:    time.Now(),
	})
}

func (er erasureObjects) PutObjectMetadata(ctx context.Context, bucket, object string, opts ObjectOptions) (ObjectInfo, error) {
	if !opts.NoLock {
		// Lock the object before updating metadata.
		lk := er.NewNSLock(bucket, object)
		lkctx, err := lk.GetLock(ctx, globalOperationTimeout)
		if err != nil {
			return ObjectInfo{}, err
		}
		ctx = lkctx.Context()
		defer lk.Unlock(lkctx)

				go func(meta metacache) {
					// Continuously update while we wait.
					t := time.NewTicker(metacacheMaxClientWait / 10)
					defer t.Stop()
					select {
					case <-ctx.Done():
						// Request is done, stop updating.
						return
					case <-t.C:
						meta.lastHandout = time.Now()
						meta, _ = rpc.UpdateMetacacheListing(ctx, meta)
					}
				}(*c)
			}
		}
	}

	if o.ID != "" && !o.Transient {

		delete(cache.iamGroupsMap, group)
		cache.iamGroupPolicyMap.Delete(group)

		cache.updatedAt = time.Now()
		return nil
	}

	gi := cache.iamGroupsMap[group]

	// Updating the group memberships cache happens in two steps:
	//
	// 1. Remove the group from each user's list of memberships.
	// 2. Add the group to each member's list of memberships.
	//

	object := ri.Name

	// set defaults for replication action based on operation being performed - actual
	// replication action can only be determined after stat on remote. This default is
	// needed for updating replication metrics correctly when target is offline.
	rAction := replicateMetadata

	rinfo = replicatedTargetInfo{
		Size:                  ri.ActualSize,
		Arn:                   tgt.ARN,

## Get Started

### 1. Prerequisites

Install MinIO - [MinIO Quickstart Guide](https://min.io/docs/minio/linux/index.html#quickstart-for-linux).

### 2. Run MinIO with compression

Compression can be enabled by updating the `compress` config settings for MinIO server config.
Config `compress` settings take extensions and mime-types to be compressed.

```bash
~ mc admin config get myminio compression

		if err != nil {
			return err
		}

		_, err = globalBucketMetadataSys.Update(ctx, bucket, bucketReplicationConfig, replCfgData)
		return c.annotatePeerErr(peer.Name, "Error updating replication configuration", err)
	}

	c.RLock()
	defer c.RUnlock()
	errMap := make(map[string]error, len(c.state.Peers))
	for d, peer := range c.state.Peers {
		if d == globalDeploymentID() {

	CheckPrecondFn      CheckPreconditionFn // only set during GetObject/HeadObject/CopyObjectPart preconditional valuation
	EvalMetadataFn      EvalMetadataFn      // only set for retention settings, meant to be used only when updating metadata in-place.
	DeleteReplication   ReplicationState    // Represents internal replication state needed for Delete replication
	Transition          TransitionOptions
	Expiration          ExpirationOptions

		return
	}

	user, exists := globalIAMSys.GetUser(ctx, accessKey)
	if exists && (user.Credentials.IsTemp() || user.Credentials.IsServiceAccount()) {
		// Updating STS credential is not allowed, and this API does not
		// support updating service accounts.
		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrAddUserInvalidArgument), r.URL)
		return
	}