diff --git a/app/handler/handler.go b/app/handler/handler.go
index 500b5e6..8ce9fde 100644
--- a/app/handler/handler.go
+++ b/app/handler/handler.go
@@ -19,6 +19,6 @@ func NewHandler(params *HandlerParams) (*Handler, error) {
 	hand := &Handler{
 		oper: params.Operator,
 	}
-	hand.logg = logger.NewLogger("handler")
+	hand.logg = logger.NewLoggerWithSubject("handler")
 	return hand, err
 }
diff --git a/app/logger/logger.go b/app/logger/logger.go
index a9133f0..75f69bc 100644
--- a/app/logger/logger.go
+++ b/app/logger/logger.go
@@ -11,25 +11,44 @@ import (
 
 var (
 	mtx    sync.Mutex
-	output io.Writer = os.Stderr
+	output io.WriteCloser = os.Stderr
 )
 
 type Logger struct {
 	subject string
+	writer  io.WriteCloser
+	mtx     *sync.Mutex
 }
 
-func NewLogger(subj string) *Logger {
+func NewLoggerWithSubject(subj string) *Logger {
 	return &Logger{
 		subject: subj,
+		writer:  output,
+		mtx:     &mtx,
 	}
 }
 
-func SetWriter(newOut io.Writer) {
+func NewLogger() *Logger {
+	return &Logger{
+		writer: output,
+		mtx:    &mtx,
+	}
+}
+
+func SetWriter(newOut io.WriteCloser) {
 	mtx.Lock()
 	output = newOut
 	mtx.Unlock()
 }
 
+func (logg *Logger) SetWriter(newOut io.WriteCloser) {
+	mtx.Lock()
+	logg.writer = newOut
+	var newMtx sync.Mutex
+	logg.mtx = &newMtx
+	mtx.Unlock()
+}
+
 func (logg *Logger) Debugf(message string, args ...any) {
 	logg.printf("debug", message, args...)
 }
@@ -49,10 +68,14 @@ func (logg *Logger) Errorf(message string, args ...any) {
 func (logg *Logger) printf(level, message string, args ...any) {
 	timestamp := time.Now().Format(time.RFC3339)
 	buffer := bytes.NewBuffer([]byte{})
-	fmt.Fprintf(buffer, "%s %s.%s: ", timestamp, logg.subject, level)
+	if logg.subject != "" {
+		fmt.Fprintf(buffer, "%s %s.%s: ", timestamp, logg.subject, level)
+	} else {
+		fmt.Fprintf(buffer, "%s %s: ", timestamp, level)
+	}
 	fmt.Fprintf(buffer, message, args...)
 	fmt.Fprintf(buffer, "\n")
-	mtx.Lock()
+	logg.mtx.Lock()
 	fmt.Fprint(output, buffer.String())
-	mtx.Unlock()
+	logg.mtx.Unlock()
 }
diff --git a/app/maindb/maindb.go b/app/maindb/maindb.go
index 14b3e24..bef62bc 100644
--- a/app/maindb/maindb.go
+++ b/app/maindb/maindb.go
@@ -19,7 +19,7 @@ type Database struct {
 func NewDatabase(datapath string) *Database {
 	return &Database{
 		datapath: datapath,
-		log:      logger.NewLogger("maindb"),
+		log:      logger.NewLoggerWithSubject("maindb"),
 	}
 }
 
diff --git a/app/operator/blob.go b/app/operator/blob.go
index 2754b65..58dc6d5 100644
--- a/app/operator/blob.go
+++ b/app/operator/blob.go
@@ -100,6 +100,7 @@ type PatchUploadResult struct {
 	Range    string
 }
 
+// TODO: partial uploading by range?
 func (oper *Operator) PatchUpload(ctx context.Context, params *PatchUploadParams) (*PatchUploadResult, int, error) {
 	var err error
 	res := &PatchUploadResult{}
@@ -129,7 +130,9 @@ func (oper *Operator) PatchUpload(ctx context.Context, params *PatchUploadParams
 	}
 	var contentLength int64
 
-	// Unfortunately, podman & github.com/containers/image don't set Content-length header for docker transport
+	// Unfortunately, podman and used github.com/containers/image don't sent
+	// Content-length header for docker transport
+
 	if params.ContentLength != "" {
 		contentLength, err = strconv.ParseInt(params.ContentLength, 10, 64)
 		if err != nil {
@@ -265,6 +268,11 @@ type DeleteBlobParams struct {
 }
 type DeleteBlobResult struct{}
 
+// Removing an individual layer is very probably to compromise data integrity.
+// - If the data layers are to be reused, this is like shooting yourself in the foot.
+// - It also prevents the manifest from being issued, as one
+// of the layers is missing.
+
 func (oper *Operator) DeleteBlob(ctx context.Context, params *DeleteBlobParams) (*DeleteBlobResult, int, error) {
 	var err error
 	res := &DeleteBlobResult{}
@@ -282,25 +290,23 @@ func (oper *Operator) DeleteBlob(ctx context.Context, params *DeleteBlobParams)
 	if err != nil {
 		return res, http.StatusInternalServerError, err
 	}
-	oper.logg.Debugf("Blob %s:%s descr exists %v", params.Name, params.Digest, descrExists)
 
 	if !descrExists {
 		return res, http.StatusNotFound, err
 	}
-
+	// Deleting blob record
+	oper.logg.Warningf("Deleting blob record %s:%s", params.Name, params.Digest)
 	err = oper.mdb.DeleteBlobByNameDigest(ctx, params.Name, params.Digest)
 	if err != nil {
 		return res, http.StatusInternalServerError, err
 	}
-	// Removing blob file if usage == 0
+	// Removing the blob binary if usage == 0
 	blobUsage, err := oper.mdb.GetBlobUsage(ctx, params.Digest)
-
-	oper.logg.Debugf("Blob %s have usage %d", params.Digest, blobUsage)
-
 	if err != nil {
 		return res, http.StatusInternalServerError, err
 	}
 	if blobUsage == 0 {
+		oper.logg.Warningf("Deleting useless blob binary %s", params.Digest)
 		oper.store.DeleteBlob(params.Digest)
 	}
 	return res, http.StatusOK, err
diff --git a/app/operator/manifest.go b/app/operator/manifest.go
index 33f9931..4a813be 100644
--- a/app/operator/manifest.go
+++ b/app/operator/manifest.go
@@ -261,6 +261,7 @@ func (oper *Operator) GetManifest(ctx context.Context, params *GetManifestParams
 
 	manifestDescr := descr.Manifest{}
 	var exists bool
+	// TODO: checking layers?
 	if stringLikeSHADigest(params.Reference) {
 		digest := normalizeSHADigest(params.Reference)
 		exists, manifestDescr, err = oper.mdb.GetManifestByDigest(ctx, params.Name, digest)
diff --git a/app/operator/operator.go b/app/operator/operator.go
index 21432a4..be588bc 100644
--- a/app/operator/operator.go
+++ b/app/operator/operator.go
@@ -23,6 +23,6 @@ func NewOperator(params *OperatorParams) (*Operator, error) {
 		mdb:   params.MainDB,
 		store: params.Store,
 	}
-	oper.logg = logger.NewLogger("operator")
+	oper.logg = logger.NewLoggerWithSubject("operator")
 	return oper, err
 }
diff --git a/app/server/server.go b/app/server/server.go
index 9541549..f2de87c 100644
--- a/app/server/server.go
+++ b/app/server/server.go
@@ -30,7 +30,7 @@ type Server struct {
 func NewServer() (*Server, error) {
 	var err error
 	srv := &Server{}
-	srv.logg = logger.NewLogger("server")
+	srv.logg = logger.NewLoggerWithSubject("server")
 	return srv, err
 }
 
diff --git a/app/service/service.go b/app/service/service.go
index 3e96237..5970d82 100644
--- a/app/service/service.go
+++ b/app/service/service.go
@@ -46,7 +46,7 @@ func NewService(params *ServiceParams) (*Service, error) {
 		portnum:  params.Portnum,
 		address:  params.Address,
 	}
-	svc.logg = logger.NewLogger("service")
+	svc.logg = logger.NewLoggerWithSubject("service")
 	return svc, err
 }
 
diff --git a/app/storage/storage.go b/app/storage/storage.go
index 6873358..03b0db7 100644
--- a/app/storage/storage.go
+++ b/app/storage/storage.go
@@ -29,7 +29,7 @@ func NewStorage(basepath string) *Storage {
 	res := &Storage{
 		basepath: basepath,
 	}
-	res.logg = logger.NewLogger("storage")
+	res.logg = logger.NewLoggerWithSubject("storage")
 	return res
 }
 
diff --git a/pkg/client/imagelife_test.go b/pkg/client/imagelife_test.go
index 062b185..e8ffc6b 100644
--- a/pkg/client/imagelife_test.go
+++ b/pkg/client/imagelife_test.go
@@ -69,7 +69,7 @@ func TestImageLife(t *testing.T) {
 		fmt.Printf("=== PushImage ===\n")
 		cli := NewClient()
 		ctx := context.Background()
-		err := cli.PushImage(ctx, "test-oci.img", srvaddr+"/foo/testapp:v123", 1*time.Second)
+		err := cli.PushImage(ctx, "test-oci.img", srvaddr+"/foo/test:123", 1*time.Second)
 		require.NoError(t, err)
 	}
 
diff --git a/test/server_test.go b/test/server_test.go
deleted file mode 100644
index 6cda40a..0000000
--- a/test/server_test.go
+++ /dev/null
@@ -1,85 +0,0 @@
-package test
-
-import (
-	"context"
-	"fmt"
-	"os"
-	"path/filepath"
-	"sync"
-	"testing"
-	"time"
-
-	"mstore/app/server"
-	"mstore/pkg/client"
-
-	"github.com/stretchr/testify/require"
-)
-
-func xxxTestService(t *testing.T) {
-	var srvport int64 = 10250
-	srvdir := t.TempDir()
-	srvaddr := fmt.Sprintf("127.0.0.1:%d", srvport)
-
-	srv, err := server.NewServer()
-	require.NoError(t, err)
-	{
-		err = srv.Configure()
-		require.NoError(t, err)
-
-		srv.SetDatadir(srvdir)
-		srv.SetLogdir(srvdir)
-		srv.SetRundir(srvdir)
-		srv.SetPort(srvport)
-
-		err = srv.Build()
-		require.NoError(t, err)
-
-		var svcWG sync.WaitGroup
-		errPipe := make(chan error, 5)
-
-		startFunc := func() {
-			err := srv.Service().Run()
-			errPipe <- err
-			svcWG.Done()
-		}
-
-		stopFunc := func() {
-			srv.Service().Stop()
-			svcWG.Wait()
-			err = <-errPipe
-			require.NoError(t, err)
-		}
-		defer stopFunc()
-
-		svcWG.Add(1)
-		go startFunc()
-		time.Sleep(1 * time.Second)
-	}
-	{
-		fmt.Printf("=== ServiceHello ===\n")
-		cli := client.NewClient()
-		ctx := context.Background()
-		ctx, _ = context.WithTimeout(ctx, 1*time.Second)
-
-		helloRes, err := cli.ServiceHello(ctx, srvaddr+"/hello")
-		require.NoError(t, err)
-		require.True(t, helloRes)
-	}
-	{
-		tmpdir := t.TempDir()
-		tmpfile := filepath.Join(tmpdir, "foo.bin")
-
-		filedata := make([]byte, 16)
-		err := os.WriteFile(tmpfile, filedata, 0666)
-		require.NoError(t, err)
-
-		fmt.Printf("=== PutFile ===\n")
-		cli := client.NewClient()
-		ctx := context.Background()
-		ctx, _ = context.WithTimeout(ctx, 1*time.Second)
-
-		err = cli.PutFile(ctx, tmpfile, srvaddr+"/foo.bin")
-		require.NoError(t, err)
-
-	}
-}