# Decommissioning

Decommissiong is a mechanism in MinIO to drain older pools (usually with old hardware) and migrate the content from such pools to a newer pools (usually better hardware). Decommissioning spreads the data across all pools - for example, if you decommission `pool1`, all the data from `pool1` spreads across `pool2` and `pool3`.

## Features

)

//go:generate msgp -file=$GOFILE -unexported
//go:generate stringer -type VersionType,ErasureAlgo -output=xl-storage-format-v2_string.go $GOFILE

const (
	// Breaking changes.
	// Newer versions cannot be read by older software.
	// This will prevent downgrades to incompatible versions.
	xlVersionMajor = 1

	// Non breaking changes.
	// Bumping this is informational, but should be done

  prefix: myprefix # (Optional) Prefix under which this job will expire objects matching the rules below.
  rules:
    - type: object  # regular objects with zero or more older versions
      name: NAME # match object names that satisfy the wildcard expression.
      olderThan: 70h # match objects older than this value
      createdBefore: "2006-01-02T15:04:05.00Z" # match objects created before "date"
      tags:
        - key: name

		t.Fatalf("Unable to create a file \"as-file\", %s", err)
	}

	fi, err := xlStorage.ReadVersion(context.Background(), "", "exists-legacy", "as-file", "", ReadOptions{})
	if err != nil {
		t.Fatalf("Unable to read older 'xl.json' content: %s", err)
	}

	if !fi.XLV1 {
		t.Fatal("Unexpected 'xl.json' content should be correctly interpreted as legacy content")
	}
}

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

package config

// One time migration code section

// SetRegion - One time migration code needed, for migrating from older config to new for server Region.
func SetRegion(c Config, name string) {
	if name == "" {
		return
	}
	c[RegionSubSys][Default] = KVS{
		KV{
			Key:   RegionName,
			Value: name,
		},
	}

)

// Legacy OPA envs
const (
	EnvIamOpaURL       = "MINIO_IAM_OPA_URL"
	EnvIamOpaAuthToken = "MINIO_IAM_OPA_AUTHTOKEN"
)

// SetPolicyOPAConfig - One time migration code needed, for migrating from older config to new for PolicyOPAConfig.
func SetPolicyOPAConfig(s config.Config, opaArgs Args) {
	if opaArgs.URL == nil || opaArgs.URL.String() == "" {
		// Do not enable if opaArgs was empty.
		return
	}

}

// UnmarshalXML decodes NoncurrentVersionExpiration
func (n *NoncurrentVersionExpiration) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
	// To handle xml with MaxNoncurrentVersions from older MinIO releases.
	// note: only one of MaxNoncurrentVersions or NewerNoncurrentVersions would be present.
	type noncurrentExpiration struct {
		XMLName                 xml.Name       `xml:"NoncurrentVersionExpiration"`

	}
	bufs := make([][]byte, len(readers))
	// Fill buffers
	b := globalBytePoolCap.Load().Get()
	shardSize := int(e.ShardSize())
	if cap(b) < len(readers)*shardSize {
		// We should always have enough capacity, but older objects may be bigger.
		globalBytePoolCap.Load().Put(b)
		b = nil
	} else {
		// Seed the buffers.
		for i := range bufs {
			bufs[i] = b[i*shardSize : (i+1)*shardSize]
		}
	}

	return &parallelReader{

// inspection to understand the root cause. E.g, this could be due to
// backend filesystem corruption.

// listOnlineDisks - returns
// - a slice of disks where disk having 'older' xl.meta (or nothing)
// are set to nil.
// - latest (in time) of the maximally occurring modTime(s), which has at least quorum occurrences.

		if err != nil {
			logger.FatalIf(err, "Unable to validate passed arguments in %s:%s",
				config.EnvVolumes, os.Getenv(config.EnvVolumes))
		}
	}
	if v == "" {
		// Fall back to older environment value MINIO_ENDPOINTS
		v, _, _, err = env.LookupEnv(config.EnvEndpoints)
		if err != nil {
			logger.FatalIf(err, "Unable to validate passed arguments in %s:%s",