diff --git a/services/backup/docker-server/contents/server/src/Reactors/server/SendLogReactor.h b/services/backup/docker-server/contents/server/src/Reactors/server/SendLogReactor.h
--- a/services/backup/docker-server/contents/server/src/Reactors/server/SendLogReactor.h
+++ b/services/backup/docker-server/contents/server/src/Reactors/server/SendLogReactor.h
@@ -2,6 +2,8 @@
 
 #include "Constants.h"
 #include "ServerReadReactorBase.h"
+#include "ServiceBlobClient.h"
+#include "Tools.h"
 
 #include "../_generated/backup.grpc.pb.h"
 #include "../_generated/backup.pb.h"
@@ -19,7 +21,9 @@
                            google::protobuf::Empty> {
   enum class State {
     USER_ID = 1,
-    LOG_CHUNK = 2,
+    BACKUP_ID = 2,
+    LOG_HASH = 3,
+    LOG_CHUNK = 4,
   };
 
   enum class PersistenceMethod {
@@ -31,12 +35,23 @@
   State state = State::USER_ID;
   PersistenceMethod persistenceMethod = PersistenceMethod::UNKNOWN;
   std::string userID;
+  std::string backupID;
+  std::string hash;
+  // either the value itself which is a dump of a single operation (if
+  // `persistedInBlob` is false) or the holder to blob (if `persistedInBlob` is
+  // true)
+  std::string value;
+  std::mutex reactorStateMutex;
+  std::condition_variable waitingForBlobClientCV;
+  std::mutex waitingForBlobClientCVMutex;
 
-  void storeInDatabase(const std::string &data) {
-  }
+  std::shared_ptr<reactor::BlobPutClientReactor> putReactor;
+  ServiceBlobClient blobClient;
 
-  void storeInBlob(const std::string &data) {
-  }
+  void storeInDatabase();
+  std::string generateHolder();
+  std::string generateLogID();
+  void initializePutReactor();
 
 public:
   using ServerReadReactorBase<backup::SendLogRequest, google::protobuf::Empty>::
@@ -45,16 +60,68 @@
   std::unique_ptr<grpc::Status>
   readRequest(backup::SendLogRequest request) override;
   void doneCallback() override;
+  void terminateCallback() override;
 };
 
+void SendLogReactor::storeInDatabase() {
+  // TODO handle attachment holders
+  database::LogItem logItem(
+      this->backupID,
+      this->generateLogID(),
+      (this->persistenceMethod == PersistenceMethod::BLOB),
+      this->value,
+      {});
+  database::DatabaseManager::getInstance().putLogItem(logItem);
+}
+
+std::string SendLogReactor::generateHolder() {
+  // TODO replace mock
+  return generateRandomString();
+}
+
+std::string SendLogReactor::generateLogID() {
+  // TODO replace mock
+  return generateRandomString();
+}
+
+void SendLogReactor::initializePutReactor() {
+  if (this->value.empty() || this->hash.empty()) {
+    throw std::runtime_error("not enough data to initialize put reactor");
+  }
+  if (this->putReactor == nullptr) {
+    this->putReactor = std::make_shared<reactor::BlobPutClientReactor>(
+        this->value, this->hash, &this->waitingForBlobClientCV);
+    this->blobClient.put(this->putReactor);
+  }
+}
+
 std::unique_ptr<grpc::Status>
 SendLogReactor::readRequest(backup::SendLogRequest request) {
+  // we make sure that the blob client's state is flushed to the main memory
+  // as there may be multiple threads from the pool taking over here
+  const std::lock_guard<std::mutex> lock(this->reactorStateMutex);
   switch (this->state) {
     case State::USER_ID: {
       if (!request.has_userid()) {
         throw std::runtime_error("user id expected but not received");
       }
       this->userID = request.userid();
+      this->state = State::BACKUP_ID;
+      return nullptr;
+    };
+    case State::BACKUP_ID: {
+      if (!request.has_backupid()) {
+        throw std::runtime_error("backup id expected but not received");
+      }
+      this->backupID = request.backupid();
+      this->state = State::LOG_HASH;
+      return nullptr;
+    };
+    case State::LOG_HASH: {
+      if (!request.has_loghash()) {
+        throw std::runtime_error("log hash expected but not received");
+      }
+      this->hash = request.loghash();
       this->state = State::LOG_CHUNK;
       return nullptr;
     };
@@ -62,18 +129,21 @@
       if (!request.has_logdata()) {
         throw std::runtime_error("log data expected but not received");
       }
-      if (this->persistenceMethod == PersistenceMethod::DB) {
-        throw std::runtime_error(
-            "storing multiple chunks in the database is not allowed");
+      std::unique_ptr<std::string> chunk =
+          std::make_unique<std::string>(std::move(*request.mutable_logdata()));
+      if (chunk->size() == 0) {
+        return std::make_unique<grpc::Status>(grpc::Status::OK);
       }
-      std::string *chunk = request.mutable_logdata();
       // decide if keep in DB or upload to blob
       if (chunk->size() <= LOG_DATA_SIZE_DATABASE_LIMIT) {
         if (this->persistenceMethod == PersistenceMethod::UNKNOWN) {
           this->persistenceMethod = PersistenceMethod::DB;
-          this->storeInDatabase(*chunk);
+          this->value = std::move(*chunk);
+          this->storeInDatabase();
+          return std::make_unique<grpc::Status>(grpc::Status::OK);
         } else if (this->persistenceMethod == PersistenceMethod::BLOB) {
-          this->storeInBlob(*chunk);
+          this->initializePutReactor();
+          this->putReactor->scheduleSendingDataChunk(std::move(chunk));
         }
         throw std::runtime_error(
             "error - invalid persistence state for chunk smaller than database "
@@ -85,17 +155,38 @@
               "error - invalid persistence state, uploading to blob should be "
               "continued but it is not");
         }
-        this->persistenceMethod = PersistenceMethod::BLOB;
-        this->storeInBlob(*chunk);
+        if (this->persistenceMethod == PersistenceMethod::UNKNOWN) {
+          this->persistenceMethod = PersistenceMethod::BLOB;
+        }
+        if (this->value.empty()) {
+          this->value = this->generateHolder();
+        }
+        this->initializePutReactor();
+        this->putReactor->scheduleSendingDataChunk(std::move(chunk));
       }
-      std::cout << "log data received " << chunk->size() << std::endl;
+
       return nullptr;
     };
   }
   throw std::runtime_error("send log - invalid state");
 }
 
+void SendLogReactor::terminateCallback() {
+  const std::lock_guard<std::mutex> lock(this->reactorStateMutex);
+
+  if (this->persistenceMethod == PersistenceMethod::DB ||
+      this->putReactor == nullptr) {
+    return;
+  }
+  this->putReactor->scheduleSendingDataChunk(std::make_unique<std::string>(""));
+  std::unique_lock<std::mutex> lock2(this->waitingForBlobClientCVMutex);
+  this->waitingForBlobClientCV.wait(lock2);
+  // store in db only when we successfully upload chunks
+  this->storeInDatabase();
+}
+
 void SendLogReactor::doneCallback() {
+  const std::lock_guard<std::mutex> lock(this->reactorStateMutex);
   // TODO implement
   std::cout << "receive logs done " << this->status.error_code() << "/"
             << this->status.error_message() << std::endl;