@@ -99,3 +98,3 @@
 	}
 
-	// from now objects should not be saved
+	// blobovnizca accepts object event if full

@@ -0,0 +91,4 @@
+		return nil, nil
+	}
+
+	blz, err := db.Open() //open db for usage, will be closed on activeDB.Close()

@@ -0,0 +12,4 @@
+	"github.com/stretchr/testify/require"
+)
+
+func TestBlobovniczaTree_Concurrency(t *testing.T) {

@@ -59,16 +60,10 @@ func (b *Blobovniczas) Delete(ctx context.Context, prm common.DeletePrm) (res co
 		return res, err
 	}
 
-	activeCache := make(map[string]struct{})

@@ -7,6 +7,8 @@ import (
 	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
 )
 
+var errClosed = logicerr.New("blobvnicza is closed")

@@ -0,0 +196,4 @@
+}
+
+type openDBCounter struct {
+	cond  *sync.Cond

@@ -170,4 +86,0 @@
-	if ok {
-		if old != nil {
-			if active.ind == b.blzLeafWidth-1 {
-				return active, logicerr.New("no more Blobovniczas")

@@ -0,0 +57,4 @@
+
+func (c *dbCache) getExisted(path string) *sharedDB {
+	c.cacheGuard.Lock()
+	defer c.cacheGuard.Unlock()

@@ -0,0 +38,4 @@
+func newActiveDBManager(dbManager *dbManager, leafWidth uint64) *activeDBManager {
+	return &activeDBManager{
+		levelToActiveDBGuard: &sync.RWMutex{},
+		levelToActiveDB:      make(map[string]*sharedDB),

@@ -0,0 +72,4 @@
+	defer m.levelToActiveDBGuard.Unlock()
+
+	for _, db := range m.levelToActiveDB {
+		db.Close()

@@ -0,0 +50,4 @@
+				require.NoError(t, err)
+
+				_, err = st.Get(context.Background(), common.GetPrm{Address: addr})
+				require.NoError(t, err) // fails very often, correlated to how many goroutines are started

@@ -23,59 +21,37 @@ func (b *Blobovniczas) Open(readOnly bool) error {
 func (b *Blobovniczas) Init() error {
 	b.log.Debug(logs.BlobovniczatreeInitializingBlobovniczas)
 
+	b.openManagers()

@@ -0,0 +78,4 @@
+	b.guard.Lock()
+	defer b.guard.Unlock()
+
+	if b.refCount == 0 {

@@ -0,0 +111,4 @@
+	result := &levelDbManager{
+		databases: make([]*sharedDB, width),
+	}
+	var idx uint64

@@ -0,0 +219,4 @@
+	c.cond.L.Lock()
+	defer c.cond.L.Unlock()
+
+	if c.count > 0 {

@@ -119,3 +62,1 @@
-	b.opened.Add(p, blz)
-
-	return blz, nil
+func (b *Blobovniczas) openBlobovnicza(p string) *sharedDB {