readsPerSec:       "Reads per second on a drive",
		writesPerSec:      "Writes per second on a drive",
		readsKBPerSec:     "Kilobytes read per second on a drive",
		writesKBPerSec:    "Kilobytes written per second on a drive",
		readsAwait:        "Average time for read requests to be served on a drive",
		writesAwait:       "Average time for write requests to be served on a drive",

In 12 drive example above, with MinIO server running in the default configuration, you can lose any of the six drives and still reconstruct the data reliably from the remaining drives.

## Why is Erasure Code useful?

          "legendFormat": "Free [{{drive}}]",
          "refId": "C"
        }
      ],
      "title": "Drive Usage",
      "type": "timeseries"
    },
    {
      "datasource": {
        "type": "prometheus",
        "uid": "${DS_PROMETHEUS}"
      },
      "description": "",
      "fieldConfig": {
        "defaults": {
          "color": {
            "mode": "palette-classic"
          },

| `minio_node_drive_total_inodes`      | Total inodes on a drive.                                 |
| `minio_node_drive_used_inodes`       | Total inodes used on a drive.                            |
| `minio_node_drive_reads_per_sec`     | Reads per second on a drive.                             |
| `minio_node_drive_reads_kb_per_sec`  | Kilobytes read per second on a drive.                    |

## Storage usage

The selection of varying data and parity drives has a direct impact on the drive space usage. With storage class, you can optimize for high
redundancy or better drive space utilization.

To get an idea of how various combinations of data and parity drives affect the storage usage, let’s take an example of a 100 MiB file stored

	if err != nil {
		if errors.Is(err, errDriveIsRoot) {
			// This is a root drive, ignore and move on
			return nil
		}
		if !errors.Is(err, errUnformattedDisk) {
			return err
		}
	}

	// Prevent parallel erasure set healing
	locker := z.NewNSLock(minioMetaBucket, fmt.Sprintf("new-drive-healing/%d/%d", poolIdx, setIdx))
	lkctx, err := locker.GetLock(ctx, newDiskHealingTimeout)
	if err != nil {

		if err != nil {
			return nil, nil, fmt.Errorf("Drive %s: %w", export, err)
		}
		// Migrate successful v1 => v2, proceed to v2 => v3
		version = formatErasureVersionV2
		fallthrough
	case formatErasureVersionV2:
		formatData, err = formatErasureMigrateV2ToV3(formatData, export, version)
		if err != nil {
			return nil, nil, fmt.Errorf("Drive %s: %w", export, err)
		}

		errs, fi, false, bucket, object, madmin.HealDeepScan)

	for diskIndex, disk := range erasureDisks {
		if diskIndex == 0 && disk != nil {
			t.Errorf("Drive not filtered as expected, drive: %d", diskIndex)
		}
		if diskIndex != 0 && disk == nil {
			t.Errorf("Drive erroneously filtered, driveIndex: %d", diskIndex)
		}
	}
	partsMetadata[0] = partsMetadataBackup // Revert before going to the next test

            if (path.isAbsolute()) {
                // path is already absolute, we're done
            } else if (path.getPath().startsWith(File.separator)) {
                // drive-relative Windows path, don't align with base dir but with drive root
                result = path.getAbsoluteFile();
            } else {
                // an ordinary relative path, align with base dir

	ssc := kvs.Get(ClassStandard)
	rrsc := kvs.Get(ClassRRS)
	return ssc != "" || rrsc != ""
}

// DefaultParityBlocks returns default parity blocks for 'drive' count
func DefaultParityBlocks(drive int) int {
	switch drive {
	case 1:
		return 0
	case 3, 2:
		return 1
	case 4, 5:
		return 2
	case 6, 7:
		return 3
	default:
		return 4
	}
}