drives.  Therefore, the number of drives you present must be a multiple of one of these numbers.  Each object is written to a single erasure-coding set.

Minio uses the largest possible EC set size which divides into the number of drives given. For example, *18 drives* are configured as *2 sets of 9 drives*, and *24 drives* are configured as *2 sets of 12 drives*.  This is true for scenarios when running MinIO as a standalone erasure coded deployment. In [distributed setup however node (affinity)...

		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",

          "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.                    |

two parity drives, 100 MiB file takes only approximately 114 MiB.

Below is a list of data/parity drives and corresponding _approximate_ storage space usage on a 16 drive MinIO deployment. The field _storage
usage ratio_ is simply the drive space used by the file after erasure-encoding, divided by actual file size.

| Total Drives (N) | Data Drives (D) | Parity Drives (P) | Storage Usage Ratio |

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package config

// UI errors
var (
	ErrInvalidXLValue = newErrFn(
		"Invalid drive path",
		"Please provide a fresh drive for single drive MinIO setup",
		"MinIO only supports fresh drive paths",
	)

	ErrInvalidBrowserValue = newErrFn(
		"Invalid console value",
		"Please check the passed value",

	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 {

			return fmt.Errorf("%s drive is already being used in another erasure deployment. (Number of drives specified: %d but the number of drives found in the %s drive's format.json: %d)",
				disks[i], len(formats), humanize.Ordinal(i+1), len(formatErasure.Erasure.Sets)*len(formatErasure.Erasure.Sets[0]))
		}
		if len(formatErasure.Erasure.Sets[0]) != setDriveCount {

		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

	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
	}
}