} 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
			}
		}
	}()
}

)

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

	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)

	if err != nil {
		logger.LogOnceIf(ctx, fmt.Errorf("%s, using default of 10s", err.Error()), "refresh-kms-master-key")
		cacheDuration = defaultCacheDuration
	}
	if cacheDuration < time.Second {
		logger.LogOnceIf(ctx, errors.New("cache duration is less than 1s, using default of 10s"), "refresh-kms-master-key")
		cacheDuration = defaultCacheDuration
	}
	timer := time.NewTimer(cacheDuration)
	defer timer.Stop()

	// 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

	//
	// 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.

				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.

				took := time.Since(refreshStart).Seconds()
				if took > maxRefreshDurationSecondsForLog {
					// Log if we took a lot of time.
					logger.Info("Site replication healing refresh took %.2fs", took)
				}

				// wait for 200 millisecond, if we are experience lot of I/O
				waitForLowIO(runtime.GOMAXPROCS(0), 200*time.Millisecond, currentHTTPIO)
			}

		return
	}
	z.SuccessorModTime, err = dc.ReadTime()
	if err != nil {
		err = msgp.WrapError(err, "SuccessorModTime")
		return
	}
	z.Fresh, err = dc.ReadBool()
	if err != nil {
		err = msgp.WrapError(err, "Fresh")
		return
	}
	z.Idx, err = dc.ReadInt()
	if err != nil {
		err = msgp.WrapError(err, "Idx")
		return
	}
	if dc.IsNil() {
		err = dc.ReadNil()

		Version string `json:"version"` // Version of 'xl' format.
		Disk    string `json:"drive"`   // Disk field carries assigned disk uuid.
		// JBOD field carries the input disk order generated the first
		// time when fresh disks were supplied.
		JBOD []string `json:"jbod"`
	} `json:"xl"` // Erasure field holds xl format.
}

// Represents the V2 backend disk structure version
// under `.minio.sys` and actual data namespace.