# Compression Guide [![Slack](https://slack.min.io/slack?type=svg)](https://slack.min.io)

MinIO server allows streaming compression to ensure efficient disk space usage.
Compression happens inflight, i.e objects are compressed before being written to disk(s).
MinIO uses [`klauspost/compress/s2`](https://github.com/klauspost/compress/tree/master/s2)
streaming compression due to its stability and performance.

				NewPutObjReader(hr),
				ObjectOptions{
					PreserveETag: part.ETag, // Preserve original ETag to ensure same metadata.
					IndexCB: func() []byte {
						return part.Index // Preserve part Index to ensure decompression works.
					},
					NoAuditLog: true,
				})
			if err != nil {
				return fmt.Errorf("rebalanceObject: PutObjectPart() %w", err)
			}
			parts[i] = CompletePart{
				ETag:       pi.ETag,

func (o *ObjectInfo) IsCompressed() bool {
	_, ok := o.UserDefined[ReservedMetadataPrefix+"compression"]
	return ok
}

// IsCompressedOK returns whether the object is compressed and can be decompressed.
func (o *ObjectInfo) IsCompressedOK() (bool, error) {
	scheme, ok := o.UserDefined[ReservedMetadataPrefix+"compression"]
	if !ok {
		return false, nil
	}
	switch scheme {

				NewPutObjReader(hr),
				ObjectOptions{
					PreserveETag: part.ETag, // Preserve original ETag to ensure same metadata.
					IndexCB: func() []byte {
						return part.Index // Preserve part Index to ensure decompression works.
					},
					NoAuditLog: true,
				})
			if err != nil {
				return fmt.Errorf("decommissionObject: PutObjectPart() %w", err)
			}
			parts[i] = CompletePart{
				ETag:           pi.ETag,

}

// RegisterDecompressor registers or overrides a custom decompressor for a
// specific method ID. If a decompressor for a given method is not found,
// [Reader] will default to looking up the decompressor at the package level.
func (r *Reader) RegisterDecompressor(method uint16, dcomp Decompressor) {
	if r.decompressors == nil {
		r.decompressors = make(map[uint16]Decompressor)
	}
	r.decompressors[method] = dcomp
}

		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrInvalidDecompressedSize: {
		Code:           "XMinioInvalidDecompressedSize",
		Description:    "The data provided is unfit for decompression",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrAddUserInvalidArgument: {
		Code:           "XMinioInvalidIAMCredentials",
		Description:    "Credential is not allowed to be same as admin access key",

touch /tmp/data/defpartsize
shred -s 500M /tmp/data/defpartsize
touch /tmp/data/mpartobj.txt
shred -s 500M /tmp/data/mpartobj.txt
echo "done"

# Enable compression for site minio1
./mc admin config set minio1 compression enable=on extensions=".txt" --insecure
./mc admin config set minio1 compression allow_encryption=off --insecure

# Create bucket in source cluster
echo "Create bucket in source MinIO instance"
./mc mb minio1/test-bucket --insecure

type Compressor func(w io.Writer) (io.WriteCloser, error)

// A Decompressor returns a new decompressing reader, reading from r.
// The [io.ReadCloser]'s Close method must be used to release associated resources.
// The Decompressor itself must be safe to invoke from multiple goroutines
// simultaneously, but each returned reader will be used only by
// one goroutine at a time.
type Decompressor func(r io.Reader) io.ReadCloser

var flateWriterPool sync.Pool

	"github.com/minio/pkg/v3/env"
)

// Config represents the compression settings.
type Config struct {
	Enabled        bool     `json:"enabled"`
	AllowEncrypted bool     `json:"allow_encryption"`
	Extensions     []string `json:"extensions"`
	MimeTypes      []string `json:"mime-types"`
}

// Compression environment variables
const (
	Extensions     = "extensions"
	AllowEncrypted = "allow_encryption"

		globalActiveCred = cfg.Credential
	}

	// Init compression config. For future migration, Compression config needs to be copied over from previous version.
	switch cfg.Version {
	case "29":
		// V29 -> V30
		cfg.Compression.Enabled = false
		cfg.Compression.Extensions = strings.Split(compress.DefaultExtensions, config.ValueSeparator)
		cfg.Compression.MimeTypes = strings.Split(compress.DefaultMimeTypes, config.ValueSeparator)