diff --git a/dbms/src/Storages/MergeTree/DataPartsExchange.cpp b/dbms/src/Storages/MergeTree/DataPartsExchange.cpp
index 03868d285e6..96db155b014 100644
--- a/dbms/src/Storages/MergeTree/DataPartsExchange.cpp
+++ b/dbms/src/Storages/MergeTree/DataPartsExchange.cpp
@@ -230,7 +230,7 @@ MergeTreeData::MutableDataPartPtr Fetcher::fetchPart(
         protocol_error = false;
 
         auto reservation = data.reserveSpaceForPart(sum_files_size);
-        return downloadPart(part_name, replica_path, to_detached, tmp_prefix_, reservation, in);
+        return downloadPart(part_name, replica_path, to_detached, tmp_prefix_, std::move(reservation), in);
     }
     catch (...) ///@TODO_IGR catch exception
     {
@@ -264,7 +264,7 @@ MergeTreeData::MutableDataPartPtr Fetcher::fetchPart(
 
     /// We don't know real size of part
     auto reservation = data.reserveOnMaxDiskWithoutReservation();
-    return downloadPart(part_name, replica_path, to_detached, tmp_prefix_, reservation, in);
+    return downloadPart(part_name, replica_path, to_detached, tmp_prefix_, std::move(reservation), in);
 }
 
 MergeTreeData::MutableDataPartPtr Fetcher::downloadPart(
@@ -272,7 +272,7 @@ MergeTreeData::MutableDataPartPtr Fetcher::downloadPart(
     const String & replica_path,
     bool to_detached,
     const String & tmp_prefix_,
-    const DiskSpaceMonitor::ReservationPtr & reservation,
+    const DiskSpaceMonitor::ReservationPtr reservation,
     PooledReadWriteBufferFromHTTP & in)
 {
 
@@ -296,8 +296,7 @@ MergeTreeData::MutableDataPartPtr Fetcher::downloadPart(
 
     part_file.createDirectory();
 
-    MergeTreeData::MutableDataPartPtr new_data_part = std::make_shared<MergeTreeData::DataPart>(data,
-                                                                                                reservation->getDisk(), part_name);
+    MergeTreeData::MutableDataPartPtr new_data_part = std::make_shared<MergeTreeData::DataPart>(data, reservation->getDisk(), part_name);
     new_data_part->relative_path = relative_part_path;
     new_data_part->is_temp = true;
 
diff --git a/dbms/src/Storages/MergeTree/DataPartsExchange.h b/dbms/src/Storages/MergeTree/DataPartsExchange.h
index c0c36cf8c37..e8d028d9dd6 100644
--- a/dbms/src/Storages/MergeTree/DataPartsExchange.h
+++ b/dbms/src/Storages/MergeTree/DataPartsExchange.h
@@ -70,7 +70,7 @@ private:
             const String & replica_path,
             bool to_detached,
             const String & tmp_prefix_,
-            const DiskSpaceMonitor::ReservationPtr & reservation,
+            const DiskSpaceMonitor::ReservationPtr reservation,
             PooledReadWriteBufferFromHTTP & in);
 
     MergeTreeData & data;
diff --git a/dbms/src/Storages/MergeTree/DiskSpaceMonitor.cpp b/dbms/src/Storages/MergeTree/DiskSpaceMonitor.cpp
index 3c1e7c42968..c897d370a49 100644
--- a/dbms/src/Storages/MergeTree/DiskSpaceMonitor.cpp
+++ b/dbms/src/Storages/MergeTree/DiskSpaceMonitor.cpp
@@ -38,6 +38,8 @@ DiskSelector::DiskSelector(const Poco::Util::AbstractConfiguration & config, con
         {
             if (path.empty())
                 throw Exception("Disk path can not be empty. Disk " + disk_name, ErrorCodes::UNKNOWN_ELEMENT_IN_CONFIG);
+            if (path.back() != '/')
+                throw Exception("Disk path must end with /. Disk " + disk_name, ErrorCodes::UNKNOWN_ELEMENT_IN_CONFIG);
             disks.emplace(disk_name, std::make_shared<const Disk>(disk_name, path, keep_free_space_bytes));
         }
     }
@@ -120,6 +122,10 @@ Schema::Volume::Volume(const Poco::Util::AbstractConfiguration & config, const s
     {
         max_data_part_size = std::numeric_limits<UInt64>::max();
     }
+    constexpr UInt64 SIZE_8MB = 1ull << 23;
+    if (max_data_part_size < SIZE_8MB) {
+        LOG_WARNING(logger, "Volume max_data_part_size is too low (" << max_data_part_size << " < " << SIZE_8MB << ")");
+    }
 }
 
 DiskSpaceMonitor::ReservationPtr Schema::Volume::reserve(UInt64 expected_size) const