diff --git a/src/benchmark/bin.rs b/src/benchmark/bin.rs
index e1d923ef1d..cb9a62c16e 100644
--- a/src/benchmark/bin.rs
+++ b/src/benchmark/bin.rs
@@ -14,6 +14,7 @@ mod prelude {
         generator::Generator,
         statistics::{Report, Statistics},
         writer::Writer,
+        Key128,
     };
     pub(crate) use clap::{App, Arg, ArgMatches};
     pub(crate) use env_logger::fmt::Color;
@@ -86,7 +87,7 @@ async fn start_app() {
         .map(|(key, data)| {
             let ltx = tx.clone();
             counter += 1;
-            writer.write(key.into(), data, ltx)
+            writer.write(key, data, ltx)
         })
         .collect();
     println!(
@@ -205,12 +206,18 @@ fn init_logger() {
         .try_init();
 }
 #[derive(Debug)]
-struct Key128(Vec<u8>);
+pub struct Key128(Vec<u8>);
 
 impl Key for Key128 {
     const LEN: u16 = 8;
 }
 
+impl AsRef<Key128> for Key128 {
+    fn as_ref(&self) -> &Self {
+        self
+    }
+}
+
 impl From<Vec<u8>> for Key128 {
     fn from(v: Vec<u8>) -> Self {
         assert_eq!(Self::LEN as usize, v.len());
diff --git a/src/benchmark/generator.rs b/src/benchmark/generator.rs
index 5f4127a4a4..02f24d4bc2 100644
--- a/src/benchmark/generator.rs
+++ b/src/benchmark/generator.rs
@@ -19,12 +19,12 @@ impl Generator {
         }
     }
 
-    pub fn next(&mut self) -> Option<(Vec<u8>, Vec<u8>)> {
+    pub fn next(&mut self) -> Option<(Key128, Vec<u8>)> {
         if self.written < self.limit * 1_000_000 {
             let key = self.written.to_be_bytes().to_vec();
             let data = self.value.clone();
             self.written += (key.len() + data.len()) as u64;
-            Some((key, data))
+            Some((Key128(key), data))
         } else {
             None
         }
diff --git a/src/benchmark/writer.rs b/src/benchmark/writer.rs
index b4f312f518..c64907baa9 100644
--- a/src/benchmark/writer.rs
+++ b/src/benchmark/writer.rs
@@ -1,11 +1,11 @@
 use super::prelude::*;
 use pearl::rio;
 
-pub struct Writer<K> {
+pub struct Writer<K: Key> {
     storage: Storage<K>,
 }
 
-impl<K> Writer<K> {
+impl<K: Key> Writer<K> {
     pub fn new(
         tmp_dir: &Path,
         max_blob_size: u64,
@@ -31,11 +31,9 @@ impl<K> Writer<K> {
         self.storage.init().await.unwrap()
     }
 
-    pub async fn write(&self, key: K, data: Vec<u8>, mut tx: Sender<Report>)
-    where
-        K: Key,
-    {
-        let mut report = Report::new(key.as_ref().len(), data.len());
+    pub async fn write(&self, key: impl AsRef<K>, data: Vec<u8>, mut tx: Sender<Report>) {
+        let kbuf: &[u8] = key.as_ref().as_ref();
+        let mut report = Report::new(kbuf.len(), data.len());
         let now = Instant::now();
         self.storage.write(key, data).await.unwrap();
         debug!("write finished");
diff --git a/src/lib.rs b/src/lib.rs
index d771c8c282..6a0bd2221c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -74,7 +74,7 @@ mod prelude {
     pub(crate) use std::collections::BTreeMap;
     pub(crate) const ORD: Ordering = Ordering::Relaxed;
 
-    pub(crate) use anyhow::{Result, Context as ErrorContexts};
+    pub(crate) use anyhow::{Context as ErrorContexts, Result};
     pub(crate) use bincode::{deserialize, serialize, serialize_into, serialized_size};
     pub(crate) use blob::{self, Blob, BloomConfig};
     pub(crate) use crc::crc32::checksum_castagnoli as crc32;
diff --git a/src/storage/core.rs b/src/storage/core.rs
index 3b58b1ca0c..28e4a3fbd4 100644
--- a/src/storage/core.rs
+++ b/src/storage/core.rs
@@ -5,8 +5,6 @@ const LOCK_FILE: &str = "pearl.lock";
 
 const O_EXCL: i32 = 128;
 
-type SaveOldBlobTask = std::pin::Pin<Box<dyn std::future::Future<Output = ()> + Send>>;
-
 /// A main storage struct.
 ///
 /// This type is clonable, cloning it will only create a new reference,
@@ -715,34 +713,29 @@ impl Safe {
         Ok(())
     }
 
-    pub(crate) async fn replace_active_blob(&mut self, blob: Box<Blob>) -> Result<SaveOldBlobTask> {
+    pub(crate) async fn replace_active_blob(&mut self, blob: Box<Blob>) -> Result<()> {
         let old_active = self
             .active_blob
             .replace(blob)
             .ok_or_else(Error::active_blob_not_set)?;
-        let blobs = self.blobs.clone();
-        Ok(Box::pin(async move {
-            let mut blobs = blobs.write().await;
-            blobs.push(*old_active);
-            // Notice: if dump of blob or indices fails, it's likely a problem with disk appeared, so
-            // all descriptors of the storage become invalid and unusable
-            // Possible solution: recreate instance of storage, when disk will be available
-            let last_blob = blobs.last_mut().unwrap();
-            if let Err(e) = last_blob.dump().await {
-                error!("Error dumping blob ({}): {}", last_blob.name(), e);
-            }
-        }))
+        self.blobs.write().await.push(*old_active);
+        Ok(())
     }
 
     pub(crate) async fn try_dump_old_blob_indexes(&mut self, sem: Arc<Semaphore>) {
         let blobs = self.blobs.clone();
         tokio::spawn(async move {
+            trace!("acquire blobs write to dump old blobs");
             let mut write_blobs = blobs.write().await;
+            trace!("dump old blobs");
             for blob in write_blobs.iter_mut() {
+                trace!("dumping old blob");
                 let _ = sem.acquire().await;
+                trace!("acquired sem for dumping old blobs");
                 if let Err(e) = blob.dump().await {
                     error!("Error dumping blob ({}): {}", blob.name(), e);
                 }
+                trace!("finished dumping old blob");
             }
         });
     }
diff --git a/src/storage/observer_worker.rs b/src/storage/observer_worker.rs
index 982fb12a64..219cc591f0 100644
--- a/src/storage/observer_worker.rs
+++ b/src/storage/observer_worker.rs
@@ -34,7 +34,10 @@ impl ObserverWorker {
     async fn tick(&mut self) -> Result<()> {
         match timeout(self.update_interval, self.receiver.recv()).await {
             Ok(Some(Msg::CloseActiveBlob)) => {
-                update_active_blob(self.inner.clone(), self.dump_sem.clone()).await?
+                update_active_blob(self.inner.clone()).await?;
+                self.inner
+                    .try_dump_old_blob_indexes(self.dump_sem.clone())
+                    .await;
             }
             Ok(None) => {
                 return Err(anyhow!(
@@ -51,13 +54,10 @@ impl ObserverWorker {
     async fn try_update(&self) -> Result<()> {
         trace!("try update active blob");
         let inner_cloned = self.inner.clone();
-        if let Some(inner) = active_blob_check(inner_cloned).await? {
-            update_active_blob(inner, self.dump_sem.clone()).await?;
+        if let Some(mut inner) = active_blob_check(inner_cloned).await? {
+            update_active_blob(inner.clone()).await?;
+            inner.try_dump_old_blob_indexes(self.dump_sem.clone()).await;
         }
-        let mut inner_mut = self.inner.clone();
-        inner_mut
-            .try_dump_old_blob_indexes(self.dump_sem.clone())
-            .await;
         Ok(())
     }
 }
@@ -91,21 +91,18 @@ async fn active_blob_check(inner: Inner) -> Result<Option<Inner>> {
     }
 }
 
-async fn update_active_blob(inner: Inner, dump_sem: Arc<Semaphore>) -> Result<()> {
+async fn update_active_blob(inner: Inner) -> Result<()> {
     let next_name = inner.next_blob_name()?;
     // Opening a new blob may take a while
+    trace!("obtaining new active blob");
     let new_active = Blob::open_new(next_name, inner.ioring, inner.config.filter())
         .await?
         .boxed();
-    let task = inner
+    inner
         .safe
         .write()
         .await
         .replace_active_blob(new_active)
         .await?;
-    tokio::spawn(async move {
-        let _res = dump_sem.acquire().await.expect("semaphore is closed");
-        task.await;
-    });
     Ok(())
 }