diff --git a/pkg/local_object_storage/blobovnicza/blobovnicza.go b/pkg/local_object_storage/blobovnicza/blobovnicza.go
index d5741fba..22168de2 100644
--- a/pkg/local_object_storage/blobovnicza/blobovnicza.go
+++ b/pkg/local_object_storage/blobovnicza/blobovnicza.go
@@ -3,6 +3,7 @@ package blobovnicza
 import (
 	"io/fs"
 	"os"
+	"sync"
 	"sync/atomic"
 	"time"
 
@@ -15,9 +16,12 @@ import (
 type Blobovnicza struct {
 	cfg
 
-	filled atomic.Uint64
+	dataSize atomic.Uint64
 
 	boltDB *bbolt.DB
+
+	opened     bool
+	controlMtx sync.Mutex
 }
 
 // Option is an option of Blobovnicza's constructor.
diff --git a/pkg/local_object_storage/blobovnicza/control.go b/pkg/local_object_storage/blobovnicza/control.go
index 79bad91e..7b555290 100644
--- a/pkg/local_object_storage/blobovnicza/control.go
+++ b/pkg/local_object_storage/blobovnicza/control.go
@@ -1,8 +1,8 @@
 package blobovnicza
 
 import (
+	"errors"
 	"fmt"
-	"os"
 	"path/filepath"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
@@ -14,7 +14,15 @@ import (
 // Open opens an internal database at the configured path with the configured permissions.
 //
 // If the database file does not exist, it will be created automatically.
+// If blobovnizca is already open, does nothing.
 func (b *Blobovnicza) Open() error {
+	b.controlMtx.Lock()
+	defer b.controlMtx.Unlock()
+
+	if b.opened {
+		return nil
+	}
+
 	b.log.Debug(logs.BlobovniczaCreatingDirectoryForBoltDB,
 		zap.String("path", b.path),
 		zap.Bool("ro", b.boltOptions.ReadOnly),
@@ -36,6 +44,7 @@ func (b *Blobovnicza) Open() error {
 
 	b.boltDB, err = bbolt.Open(b.path, b.perm, b.boltOptions)
 	if err == nil {
+		b.opened = true
 		b.metrics.IncOpenBlobovnizcaCount()
 	}
 
@@ -45,20 +54,28 @@ func (b *Blobovnicza) Open() error {
 // Init initializes internal database structure.
 //
 // If Blobovnicza is already initialized, no action is taken.
+// Blobovnizca must be open, otherwise an error will return.
 func (b *Blobovnicza) Init() error {
+	b.controlMtx.Lock()
+	defer b.controlMtx.Unlock()
+
+	if !b.opened {
+		return errors.New("blobovnizca is not open")
+	}
+
 	b.log.Debug(logs.BlobovniczaInitializing,
 		zap.Uint64("object size limit", b.objSizeLimit),
 		zap.Uint64("storage size limit", b.fullSizeLimit),
 	)
 
-	if size := b.filled.Load(); size != 0 {
+	if size := b.dataSize.Load(); size != 0 {
 		b.log.Debug(logs.BlobovniczaAlreadyInitialized, zap.Uint64("size", size))
 		return nil
 	}
 
 	if !b.boltOptions.ReadOnly {
 		err := b.boltDB.Update(func(tx *bbolt.Tx) error {
-			return b.iterateBucketKeys(func(lower, upper uint64, key []byte) (bool, error) {
+			return b.iterateBucketKeys(true, func(lower, upper uint64, key []byte) (bool, error) {
 				// create size range bucket
 
 				rangeStr := stringifyBounds(lower, upper)
@@ -79,27 +96,49 @@ func (b *Blobovnicza) Init() error {
 		}
 	}
 
-	info, err := os.Stat(b.path)
+	return b.initializeSize()
+}
+
+func (b *Blobovnicza) initializeSize() error {
+	var size uint64
+	err := b.boltDB.View(func(tx *bbolt.Tx) error {
+		return b.iterateAllBuckets(tx, func(lower, upper uint64, b *bbolt.Bucket) (bool, error) {
+			size += uint64(b.Stats().KeyN) * upper
+			return false, nil
+		})
+	})
 	if err != nil {
 		return fmt.Errorf("can't determine DB size: %w", err)
 	}
-
-	sz := uint64(info.Size())
-	b.filled.Store(sz)
-	b.metrics.AddSize(sz)
-	return err
+	b.dataSize.Store(size)
+	b.metrics.AddSize(size)
+	return nil
 }
 
 // Close releases all internal database resources.
+//
+// If blobovnizca is already closed, does nothing.
 func (b *Blobovnicza) Close() error {
+	b.controlMtx.Lock()
+	defer b.controlMtx.Unlock()
+
+	if !b.opened {
+		return nil
+	}
+
 	b.log.Debug(logs.BlobovniczaClosingBoltDB,
 		zap.String("path", b.path),
 	)
 
-	err := b.boltDB.Close()
-	if err == nil {
-		b.metrics.DecOpenBlobovnizcaCount()
-		b.metrics.SubSize(b.filled.Load())
+	if err := b.boltDB.Close(); err != nil {
+		return err
 	}
-	return err
+
+	b.metrics.DecOpenBlobovnizcaCount()
+	b.metrics.SubSize(b.dataSize.Load())
+	b.dataSize.Store(0)
+
+	b.opened = false
+
+	return nil
 }
diff --git a/pkg/local_object_storage/blobovnicza/delete.go b/pkg/local_object_storage/blobovnicza/delete.go
index 419e073c..f332173c 100644
--- a/pkg/local_object_storage/blobovnicza/delete.go
+++ b/pkg/local_object_storage/blobovnicza/delete.go
@@ -46,33 +46,22 @@ func (b *Blobovnicza) Delete(ctx context.Context, prm DeletePrm) (DeleteRes, err
 	addrKey := addressKey(prm.addr)
 
 	found := false
+	var sizeUpperBound uint64
+	var sizeLowerBound uint64
+	var dataSize uint64
 
 	err := b.boltDB.Update(func(tx *bbolt.Tx) error {
-		return b.iterateBuckets(tx, func(lower, upper uint64, buck *bbolt.Bucket) (bool, error) {
+		return b.iterateAllBuckets(tx, func(lower, upper uint64, buck *bbolt.Bucket) (bool, error) {
 			objData := buck.Get(addrKey)
 			if objData == nil {
 				// object is not in bucket => continue iterating
 				return false, nil
 			}
-
-			sz := uint64(len(objData))
-
-			// remove object from the bucket
-			err := buck.Delete(addrKey)
-
-			if err == nil {
-				b.log.Debug(logs.BlobovniczaObjectWasRemovedFromBucket,
-					zap.String("binary size", stringifyByteSize(sz)),
-					zap.String("range", stringifyBounds(lower, upper)),
-				)
-				// decrease fullness counter
-				b.decSize(sz)
-			}
-
+			dataSize = uint64(len(objData))
+			sizeLowerBound = lower
+			sizeUpperBound = upper
 			found = true
-
-			// stop iteration
-			return true, err
+			return true, buck.Delete(addrKey)
 		})
 	})
 
@@ -80,5 +69,13 @@ func (b *Blobovnicza) Delete(ctx context.Context, prm DeletePrm) (DeleteRes, err
 		return DeleteRes{}, new(apistatus.ObjectNotFound)
 	}
 
+	if err == nil && found {
+		b.log.Debug(logs.BlobovniczaObjectWasRemovedFromBucket,
+			zap.String("binary size", stringifyByteSize(dataSize)),
+			zap.String("range", stringifyBounds(sizeLowerBound, sizeUpperBound)),
+		)
+		b.decSize(sizeUpperBound)
+	}
+
 	return DeleteRes{}, err
 }
diff --git a/pkg/local_object_storage/blobovnicza/iterate.go b/pkg/local_object_storage/blobovnicza/iterate.go
index c2031ea5..b29ccb43 100644
--- a/pkg/local_object_storage/blobovnicza/iterate.go
+++ b/pkg/local_object_storage/blobovnicza/iterate.go
@@ -3,6 +3,7 @@ package blobovnicza
 import (
 	"context"
 	"fmt"
+	"math"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-observability/tracing"
 	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
@@ -11,28 +12,32 @@ import (
 	"go.opentelemetry.io/otel/trace"
 )
 
-func (b *Blobovnicza) iterateBuckets(tx *bbolt.Tx, f func(uint64, uint64, *bbolt.Bucket) (bool, error)) error {
-	return b.iterateBucketKeys(func(lower uint64, upper uint64, key []byte) (bool, error) {
+// iterateAllBuckets iterates all buckets in db
+//
+// If the maximum size of the object (b.objSizeLimit) has been changed to lower value,
+// then there may be more buckets than the current limit of the object size.
+func (b *Blobovnicza) iterateAllBuckets(tx *bbolt.Tx, f func(uint64, uint64, *bbolt.Bucket) (bool, error)) error {
+	return b.iterateBucketKeys(false, func(lower uint64, upper uint64, key []byte) (bool, error) {
 		buck := tx.Bucket(key)
 		if buck == nil {
-			// expected to happen:
-			//  - before initialization step (incorrect usage by design)
-			//  - if DB is corrupted (in future this case should be handled)
-			return false, fmt.Errorf("(%T) could not get bucket %s", b, stringifyBounds(lower, upper))
+			return true, nil
 		}
 
 		return f(lower, upper, buck)
 	})
 }
 
-func (b *Blobovnicza) iterateBucketKeys(f func(uint64, uint64, []byte) (bool, error)) error {
-	return b.iterateBounds(func(lower, upper uint64) (bool, error) {
+func (b *Blobovnicza) iterateBucketKeys(useObjLimitBound bool, f func(uint64, uint64, []byte) (bool, error)) error {
+	return b.iterateBounds(useObjLimitBound, func(lower, upper uint64) (bool, error) {
 		return f(lower, upper, bucketKeyFromBounds(upper))
 	})
 }
 
-func (b *Blobovnicza) iterateBounds(f func(uint64, uint64) (bool, error)) error {
-	objLimitBound := upperPowerOfTwo(b.objSizeLimit)
+func (b *Blobovnicza) iterateBounds(useObjLimitBound bool, f func(uint64, uint64) (bool, error)) error {
+	var objLimitBound uint64 = math.MaxUint64
+	if useObjLimitBound {
+		objLimitBound = upperPowerOfTwo(b.objSizeLimit)
+	}
 
 	for upper := firstBucketBound; upper <= max(objLimitBound, firstBucketBound); upper *= 2 {
 		var lower uint64
diff --git a/pkg/local_object_storage/blobovnicza/put.go b/pkg/local_object_storage/blobovnicza/put.go
index cc816b3e..b8cc9954 100644
--- a/pkg/local_object_storage/blobovnicza/put.go
+++ b/pkg/local_object_storage/blobovnicza/put.go
@@ -61,7 +61,7 @@ func (b *Blobovnicza) Put(ctx context.Context, prm PutPrm) (PutRes, error) {
 	defer span.End()
 
 	sz := uint64(len(prm.objData))
-	bucketName := bucketForSize(sz)
+	bucketName, upperBound := bucketForSize(sz)
 	key := addressKey(prm.addr)
 
 	err := b.boltDB.Batch(func(tx *bbolt.Tx) error {
@@ -85,7 +85,7 @@ func (b *Blobovnicza) Put(ctx context.Context, prm PutPrm) (PutRes, error) {
 		return nil
 	})
 	if err == nil {
-		b.incSize(sz)
+		b.incSize(upperBound)
 	}
 
 	return PutRes{}, err
diff --git a/pkg/local_object_storage/blobovnicza/sizes.go b/pkg/local_object_storage/blobovnicza/sizes.go
index 7e10b728..482242c3 100644
--- a/pkg/local_object_storage/blobovnicza/sizes.go
+++ b/pkg/local_object_storage/blobovnicza/sizes.go
@@ -28,8 +28,9 @@ func bucketKeyFromBounds(upperBound uint64) []byte {
 	return buf[:ln]
 }
 
-func bucketForSize(sz uint64) []byte {
-	return bucketKeyFromBounds(upperPowerOfTwo(sz))
+func bucketForSize(sz uint64) ([]byte, uint64) {
+	upperBound := upperPowerOfTwo(sz)
+	return bucketKeyFromBounds(upperBound), upperBound
 }
 
 func upperPowerOfTwo(v uint64) uint64 {
@@ -40,15 +41,15 @@ func upperPowerOfTwo(v uint64) uint64 {
 }
 
 func (b *Blobovnicza) incSize(sz uint64) {
-	b.filled.Add(sz)
+	b.dataSize.Add(sz)
 	b.metrics.AddSize(sz)
 }
 
 func (b *Blobovnicza) decSize(sz uint64) {
-	b.filled.Add(^(sz - 1))
+	b.dataSize.Add(^(sz - 1))
 	b.metrics.SubSize(sz)
 }
 
 func (b *Blobovnicza) full() bool {
-	return b.filled.Load() >= b.fullSizeLimit
+	return b.dataSize.Load() >= b.fullSizeLimit
 }
diff --git a/pkg/local_object_storage/blobovnicza/sizes_test.go b/pkg/local_object_storage/blobovnicza/sizes_test.go
index 2bf451f1..d2f576fd 100644
--- a/pkg/local_object_storage/blobovnicza/sizes_test.go
+++ b/pkg/local_object_storage/blobovnicza/sizes_test.go
@@ -34,7 +34,8 @@ func TestSizes(t *testing.T) {
 			upperBound: 4 * firstBucketBound,
 		},
 	} {
-		require.Equal(t, bucketKeyFromBounds(item.upperBound), bucketForSize(item.sz))
+		key, _ := bucketForSize(item.sz)
+		require.Equal(t, bucketKeyFromBounds(item.upperBound), key)
 	}
 }