}

// Trim leading and trailing spaces and replace sequential spaces with one space, following Trimall()
// in http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
func signV4TrimAll(input string) string {
	// Compress adjacent spaces (a space is determined by
	// unicode.IsSpace() internally here) to one space and return
	return strings.Join(strings.Fields(input), " ")
}

		Free:   uint64(s.Frsize) * uint64(s.Bavail),
		Files:  uint64(s.Files),
		Ffree:  uint64(s.Ffree),
		FSType: string(s.Fstypename[:]),
	}
	if info.Free > info.Total {
		return info, fmt.Errorf("detected free space (%d) > total drive space (%d), fs corruption at (%s). please run 'fsck'", info.Free, info.Total, path)
	}
	info.Used = info.Total - info.Free
	return info, nil
}

// GetDriveStats returns IO stats of the drive by its major:minor

		Files:  uint64(s.F_files),
		Ffree:  uint64(s.F_ffree),
		FSType: getFSType(s.F_fstypename[:]),
	}
	if info.Free > info.Total {
		return info, fmt.Errorf("detected free space (%d) > total drive space (%d), fs corruption at (%s). please run 'fsck'", info.Free, info.Total, path)
	}
	info.Used = info.Total - info.Free
	return info, nil
}

// GetDriveStats returns IO stats of the drive by its major:minor

		)

		// Total available space in the disk
		ch <- prometheus.MustNewConstMetric(
			prometheus.NewDesc(
				prometheus.BuildFQName(diskNamespace, "storage", "available"),
				"Total available space left on the drive",
				[]string{"disk"}, nil),
			prometheus.GaugeValue,
			float64(disk.AvailableSpace),
			disk.DrivePath,
		)

		// Total storage space of the disk
		ch <- prometheus.MustNewConstMetric(

	// Check for overflows.
	// https://github.com/minio/minio/issues/8035
	// XFS can show wrong values at times error out
	// in such scenarios.
	if info.Free > info.Total {
		return info, fmt.Errorf("detected free space (%d) > total drive space (%d), fs corruption at (%s). please run 'fsck'", info.Free, info.Total, path)
	}
	info.Used = info.Total - info.Free

	if firstTime {
		bfs, err := blockdevice.NewDefaultFS()
		if err == nil {

// rebalanceStats contains per-pool rebalance statistics like number of objects,
// versions and bytes rebalanced out of a pool
type rebalanceStats struct {
	InitFreeSpace uint64 `json:"initFreeSpace" msg:"ifs"` // Pool free space at the start of rebalance
	InitCapacity  uint64 `json:"initCapacity" msg:"ic"`   // Pool capacity at the start of rebalance

	return -1
}

// getServerPoolsAvailableSpace will return the available space of each pool after storing the content.
// If there is not enough space the pool will return 0 bytes available.
// The size of each will be multiplied by the number of sets.
// Negative sizes are seen as 0 bytes.

func (e SignatureDoesNotMatch) Error() string {
	return "The request signature we calculated does not match the signature you provided. Check your key and signing method."
}

// StorageFull storage ran out of space.
type StorageFull struct{}

func (e StorageFull) Error() string {
	return "Storage reached its minimum free drive threshold."
}

// SlowDown  too many file descriptors open or backend busy .

		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrAuthHeaderEmpty: {
		Code:           "InvalidArgument",
		Description:    "Authorization header is invalid -- one and only one ' ' (space) required.",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrMissingDateHeader: {
		Code:           "AccessDenied",
		Description:    "AWS authentication requires a valid Date or x-amz-date header",

		cacheInterval:    1 * time.Minute,
		metricsGroupOpts: opts,
	}
	mg.RegisterRead(func(ctx context.Context) (metrics []MetricV2) {
		objLayer := newObjectLayerFn()

		// Fetch disk space info, ignore errors
		metrics = make([]MetricV2, 0, 10)
		storageInfo := objLayer.StorageInfo(ctx, true)
		onlineDrives, offlineDrives := getOnlineOfflineDisksStats(storageInfo.Disks)