}

// PutObject - creates an object upon reading from the input stream
// until EOF, erasure codes the data across all disk and additionally
// writes `xl.meta` which carries the necessary metadata for future
// object operations.
func (er erasureObjects) PutObject(ctx context.Context, bucket string, object string, data *PutObjReader, opts ObjectOptions) (objInfo ObjectInfo, err error) {

type formatErasureV1 struct {
	formatMetaV1
	Erasure struct {
		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.
}

// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

// Format related consts
const (
	// Format config file carries backend format specific details.
	formatConfigFile = "format.json"
)

const (
	// Version of the formatMetaV1
	formatMetaVersionV1 = "1"
)

// format.json currently has the format:
// {

	FSType     string
	RootDisk   bool
	Healing    bool
	Scanning   bool
	Endpoint   string
	MountPath  string
	ID         string
	Rotational bool
	Metrics    DiskMetrics
	Error      string // carries the error over the network
}

// DiskMetrics has the information about XL Storage APIs
// the number of calls of each API and the moving average of
// the duration of each API.
type DiskMetrics struct {

2021602 E BX46 Parkchester 3709 2106 284 2 Bronx 028400 2028400 E BX37 Van Nest-Morris Park-Westchester Square 3704 3389497 2 2014-03-15 16:46:28 2014-03-15 16:54:39 N 1 -73.860969543457031 40.833728790283203 -73.851020812988281 40.850376129150391 1 1.76 8.5 0 0.5 3 0 12 1 1 182 242 green 0.00 0.0 0.0 58 42 8.95 1306 216.02 2 Bronx 021602 2021602 E BX46 Parkchester 3709 486 286 2 Bronx 028600 2028600 I BX37 Van Nest-Morris Park-Westchester Square 3704 3389498 2 2014-03-03 21:23:08 2014-03-03 21:34:43...

	// bigFileThreshold is the point where we add readahead to put operations.
	bigFileThreshold = 128 * humanize.MiByte

	// XL metadata file carries per object metadata.
	xlStorageFormatFile = "xl.meta"

	// XL metadata file backup file carries previous per object metadata.
	xlStorageFormatFileBackup = "xl.meta.bkp"
)

var alignedBuf []byte

func init() {

This file is the source of truth for each `version` at rest. `xl.meta` is a msgpack file serialized from a
well defined data structure. To understand `xl.meta` here are the few things to start with

`xl.meta` carries first 8 bytes an XL header which describes the current format and the format version,
allowing the unmarshaller's to automatically use the right data structures to parse the subsequent content in the stream.

### v1.0

import (
	"encoding/binary"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"time"

	"github.com/cespare/xxhash/v2"
	jsoniter "github.com/json-iterator/go"
)

// XL constants.
const (
	// XL metadata file carries per object metadata.
	xlStorageFormatFileV1 = "xl.json"
)

// Valid - tells us if the format is sane by validating
// format version and erasure coding information.
func (m *xlMetaV1Object) valid() bool {

func RegisterDefaultKVS(kvsMap map[string]KVS) {
	for subSys, kvs := range kvsMap {
		DefaultKVS[subSys] = kvs
	}
}

// HelpSubSysMap - help for all individual KVS for each sub-systems
// also carries a special empty sub-system which dumps
// help for each sub-system key.
var HelpSubSysMap = map[string]HelpKVS{}

// RegisterHelpSubSys - this function saves
// input help KVS for each sub-system globally,

### Upgrade Checklist

- Test all upgrades in a lower environment (DEV, QA, UAT) before applying to production. Performing blind upgrades in production environments carries significant risk.