IsOnline() bool

	// Returns the last time this disk (re)-connected
	LastConn() time.Time

	// Indicates if disk is local or not.
	IsLocal() bool

	// Returns hostname if disk is remote.
	Hostname() string

	// Returns the entire endpoint.
	Endpoint() Endpoint

	// Close the disk, mark it purposefully closed, only implemented for remote disks.
	Close() error

	// Returns the unique 'uuid' of this disk.

}

func writeAllMetadataWithRevert(ctx context.Context, disks []StorageAPI, origbucket, bucket, prefix string, files []FileInfo, quorum int, revert bool) ([]StorageAPI, error) {
	g := errgroup.WithNErrs(len(disks))

	// Start writing `xl.meta` to all disks in parallel.
	for index := range disks {
		index := index
		g.Go(func() error {
			if disks[index] == nil {
				return errDiskNotFound
			}

		return nil
	}

	for _, disk := range driveMetrics.storageInfo.Disks {
		labels := []string{
			driveL, disk.DrivePath,
			poolIndexL, strconv.Itoa(disk.PoolIndex),
			setIndexL, strconv.Itoa(disk.SetIndex),
			driveIndexL, strconv.Itoa(disk.DiskIndex),
		}

		m.setDriveBasicMetrics(disk, labels)
		if dm, found := driveMetrics.ioStats[disk.DrivePath]; found {
			m.setDriveIOStatMetrics(dm, labels)

		}
		totalCap += disk.TotalSpace
		totalFree += disk.AvailableSpace

		diskStats[disk.PoolIndex].AvailableSpace += disk.AvailableSpace
		diskStats[disk.PoolIndex].TotalSpace += disk.TotalSpace
	}
	r.PercentFreeGoal = float64(totalFree) / float64(totalCap)

	now := time.Now()
	for idx := range z.serverPools {
		r.PoolStats[idx] = &rebalanceStats{
			Buckets:           make([]string, len(buckets)),

	globalLocalDrivesMu.RUnlock()

	// Initialize sync waitgroup.
	g := errgroup.WithNErrs(len(localDrives))

	// Disk states slices
	beforeState := make([]string, len(localDrives))
	afterState := make([]string, len(localDrives))

	// Make a volume entry on all underlying storage disks.
	for index := range localDrives {
		index := index
		g.Go(func() (serr error) {
			if localDrives[index] == nil {

	healMRFMetaFormat    = 1
	healMRFMetaVersionV1 = 1
)

// PartialOperation is a successful upload/delete of an object
// but not written in all disks (having quorum)
type PartialOperation struct {
	Bucket              string
	Object              string
	VersionID           string
	Versions            []byte
	SetIndex, PoolIndex int
	Queued              time.Time

}

// currentPathUpdater provides a lightweight update function for keeping track of
// current objects for each disk.
// Returns a function that can be used to update the current object
// and a function to call to when processing finished.
func (p *scannerMetrics) currentPathUpdater(disk, initial string) (update func(path string), done func()) {
	initialPtr := unsafe.Pointer(&initial)
	tracker := &currentPathTracker{

func initTestServerWithBackend(ctx context.Context, t TestErrHandler, testServer TestServer, objLayer ObjectLayer, disks []string) TestServer {
	// Test Server needs to start before formatting of disks.
	// Get credential.
	credentials := globalActiveCred
	if !globalReplicationPool.IsSet() {
		globalReplicationPool.Set(nil)
	}
	testServer.Obj = objLayer
	testServer.rawDiskPaths = disks

	// Maximum size of default bucket encryption configuration allowed
	maxBucketSSEConfigSize = 1 * humanize.MiByte

	// diskFillFraction is the fraction of a disk we allow to be filled.
	diskFillFraction = 0.99

	// diskReserveFraction is the fraction of a disk where we will fill other server pools first.
	// If all pools reach this, we will use all pools with regular placement.
	diskReserveFraction = 0.15

	// i.e if we do no return here in such a case, reduceWriteQuorumErrs() would
	// return a quorum error to HealFile().
	nilCount := countErrs(p.errs, nil)
	if nilCount >= p.writeQuorum {
		return nil
	}

	writeErr := reduceWriteQuorumErrs(ctx, p.errs, objectOpIgnoredErrs, p.writeQuorum)