switch cfg.Name {
	case storageclass.STANDARD, storageclass.RRS:
		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, errTierReservedName), r.URL)
		return
	}

	// Refresh from the disk in case we had missed notifications about edits from peers.
	if err := globalTierConfigMgr.Reload(ctx, objAPI); err != nil {
		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
		return
	}

	if err != nil {
		return nil, err
	}

	// Refresh obtains a fresh token
	err = spt.Refresh()
	if err != nil {
		return nil, err
	}

	tc := azblob.NewTokenCredential(spt.Token().AccessToken, func(tc azblob.TokenCredential) time.Duration {
		err := spt.Refresh()
		if err != nil {
			return 0
		}
		// set the new token value

)

type arnTarget struct {
	Client      *TargetClient
	lastRefresh time.Time
}

// arnErrs represents number of errors seen for a ARN and if update is in progress
// to refresh remote targets from bucket metadata.
type arnErrs struct {
	count            int64
	updateInProgress bool
	bucket           string
}

// BucketTargetSys represents bucket targets subsystem

	// GlobalStaleUploadsCleanupInterval - Cleanup interval when the stale uploads cleanup is initiated.
	GlobalStaleUploadsCleanupInterval = time.Hour * 6 // 6 hrs.

	// Refresh interval to update in-memory iam config cache.
	globalRefreshIAMInterval = 10 * time.Minute

	// Limit of location constraint XML for unauthenticated PUT bucket operations.
	maxLocationConstraintSize = 3 * humanize.MiByte

		} else {
			dnsTTL = 10 * time.Minute
		}
	}

	// Call to refresh will refresh names in cache.
	go func() {
		// Baremetal setups set DNS refresh window up to dnsTTL duration.
		t := time.NewTicker(dnsTTL)
		defer t.Stop()
		for {
			select {
			case <-t.C:
				globalDNSCache.Refresh()

			case <-GlobalContext.Done():
				return
			}
		}
	}()
}

				iamLogIf(ctx, fmt.Errorf("Failure in periodic refresh for IAM (took %.2fs): %v", time.Since(refreshStart).Seconds(), err), logger.WarningKind)
			} else {
				took := time.Since(refreshStart).Seconds()
				if took > maxDurationSecondsForLog {
					// Log if we took a lot of time to load.
					logger.Info("IAM refresh took %.2fs", took)
				}
			}

			// Purge expired STS credentials.

	defer config.Unlock()

	switch err {
	case nil:
		break
	case errConfigNotFound: // nothing to reload
		// To maintain the invariance that lastRefreshedAt records the
		// timestamp of last successful refresh
		config.lastRefreshedAt = UTCNow()
		return nil
	default:
		return err
	}

	// Reset drivercache built using current config
	for k := range config.drivercache {
		delete(config.drivercache, k)

var errSkipFile = errors.New("skip this file")

var errIgnoreFileContrib = errors.New("ignore this file's contribution toward data-usage")

// errXLBackend XL drive mode requires fresh deployment.
var errXLBackend = errors.New("XL backend requires fresh drive")

// StorageErr represents error generated by xlStorage call.
type StorageErr string

func (h StorageErr) Error() string {
	return string(h)
}

	//
	// An in-memory cache must be replaced only if we know for sure that the
	// values loaded from disk are not stale. They might be stale if the
	// cached.updatedAt is more recent than the refresh cycle began.
	if cache.updatedAt.Before(loadedAt) {
		// No one has updated anything since the config was loaded,
		// so we just replace whatever is on the disk into memory.

	}

	// Fill all the necessary metadata.
	// Update `xl.meta` content on each disks.
	for index := range partsMetadata {
		partsMetadata[index].Size = n
		partsMetadata[index].Fresh = true
		partsMetadata[index].ModTime = modTime
		partsMetadata[index].Metadata = opts.UserDefined
	}

	// Set an additional header when data is inlined.
	for index := range partsMetadata {