diff --git a/internal/core/bench/bench_search.cpp b/internal/core/bench/bench_search.cpp
index cd581e07fc9f3a70d6b6b3d7a5a90bb0618c1768..26b4eb3491924477831c3ab03d014778176b2920 100644
--- a/internal/core/bench/bench_search.cpp
+++ b/internal/core/bench/bench_search.cpp
@@ -69,7 +69,9 @@ Search_SmallIndex(benchmark::State& state) {
 
     auto is_small_index = state.range(0);
     auto chunk_size = state.range(1) * 1024;
-    auto segment = CreateGrowingSegment(schema, chunk_size);
+    auto segconf = SegcoreConfig::default_config();
+    segconf.set_size_per_chunk(chunk_size);
+    auto segment = CreateGrowingSegment(schema, segconf);
     if (!is_small_index) {
         segment->debug_disable_small_index();
     }
diff --git a/internal/core/src/common/CMakeLists.txt b/internal/core/src/common/CMakeLists.txt
index f07553085e183bf5751e055050dd612ab6a14d95..6b867b18b42ae59746bcf486368b4ada03b1eda1 100644
--- a/internal/core/src/common/CMakeLists.txt
+++ b/internal/core/src/common/CMakeLists.txt
@@ -7,4 +7,4 @@ set(COMMON_SRC
 add_library(milvus_common
         ${COMMON_SRC}
         )
-target_link_libraries(milvus_common milvus_proto)
+target_link_libraries(milvus_common milvus_proto yaml-cpp)
diff --git a/internal/core/src/common/SystemProperty.cpp b/internal/core/src/common/SystemProperty.cpp
index e6fc4e29f425116e3e4c9dcbf08d1e61209457dd..2d7902c91467af69701c6f3e0f6f2727b0738451 100644
--- a/internal/core/src/common/SystemProperty.cpp
+++ b/internal/core/src/common/SystemProperty.cpp
@@ -11,6 +11,8 @@
 
 #include "common/SystemProperty.h"
 #include "utils/EasyAssert.h"
+#include <yaml-cpp/yaml.h>
+#include "common/Types.h"
 
 namespace milvus {
 class SystemPropertyImpl : public SystemProperty {
@@ -50,19 +52,20 @@ class SystemPropertyImpl : public SystemProperty {
         return name_to_types_.count(field_name);
     }
 
-    friend const SystemProperty&
-    SystemProperty::Instance();
+    friend SystemPropertyImpl&
+    InstanceImpl();
 
  private:
     std::map<FieldName, SystemFieldType> name_to_types_;
     std::map<FieldId, SystemFieldType> id_to_types_;
 };
 
-const SystemProperty&
-SystemProperty::Instance() {
+SystemPropertyImpl&
+InstanceImpl() {
     static auto impl = [] {
         SystemPropertyImpl impl;
         using Type = SystemFieldType;
+
         impl.name_to_types_.emplace(FieldName("RowID"), Type::RowId);
         impl.id_to_types_.emplace(FieldId(0), Type::RowId);
 
@@ -73,4 +76,10 @@ SystemProperty::Instance() {
     }();
     return impl;
 }
+
+const SystemProperty&
+SystemProperty::Instance() {
+    return InstanceImpl();
+}
+
 };  // namespace milvus
diff --git a/internal/core/src/common/SystemProperty.h b/internal/core/src/common/SystemProperty.h
index 4dd8d7b5354023c2c7d2ffb1333e8c549a68b1db..6c45e8ecbe2b118cb291a4295b37b86816523a41 100644
--- a/internal/core/src/common/SystemProperty.h
+++ b/internal/core/src/common/SystemProperty.h
@@ -11,6 +11,8 @@
 
 #pragma once
 #include "common/Types.h"
+#include "utils/Json.h"
+#include <string>
 
 namespace milvus {
 
@@ -22,8 +24,20 @@ enum class SystemFieldType {
 
 class SystemProperty {
  public:
+    SystemProperty() = default;
+    ~SystemProperty() = default;
+
     static const SystemProperty&
     Instance();
+    SystemProperty(const SystemProperty&) = delete;
+
+    SystemProperty&
+    operator=(const SystemProperty&) = delete;
+
+ protected:
+    SystemProperty(SystemProperty&&) = default;
+    SystemProperty&
+    operator=(SystemProperty&&) = default;
 
  public:
     virtual bool
@@ -42,4 +56,7 @@ class SystemProperty {
     IsSystem(FieldName field_name) const = 0;
 };
 
+void
+InitalizeSegcore(const std::string& segcore_yaml_path);
+
 }  // namespace milvus
diff --git a/internal/core/src/query/SearchOnGrowing.cpp b/internal/core/src/query/SearchOnGrowing.cpp
index 1e6f1c7252b159e71c2dd10c42b7e0e57d24166d..e043731931132afd15afa9cbc9d23a274d308263 100644
--- a/internal/core/src/query/SearchOnGrowing.cpp
+++ b/internal/core/src/query/SearchOnGrowing.cpp
@@ -77,7 +77,7 @@ FloatSearch(const segcore::SegmentGrowingImpl& segment,
     if (indexing_record.is_in(vecfield_offset)) {
         auto max_indexed_id = indexing_record.get_finished_ack();
         const auto& field_indexing = indexing_record.get_vec_field_indexing(vecfield_offset);
-        auto search_conf = field_indexing.get_search_conf(topK);
+        auto search_conf = field_indexing.get_search_params(topK);
         Assert(vec_ptr->get_size_per_chunk() == field_indexing.get_size_per_chunk());
 
         for (int chunk_id = current_chunk_id; chunk_id < max_indexed_id; ++chunk_id) {
diff --git a/internal/core/src/segcore/CMakeLists.txt b/internal/core/src/segcore/CMakeLists.txt
index fc796361d1d8dcfa905ff5a79c5123da961ea0aa..10ed510ca85f84fd06e610cbba4d7d450e587cd8 100644
--- a/internal/core/src/segcore/CMakeLists.txt
+++ b/internal/core/src/segcore/CMakeLists.txt
@@ -14,7 +14,7 @@ set(SEGCORE_FILES
         load_index_c.cpp
         SealedIndexingRecord.cpp
         SegmentInterface.cpp
-        )
+        SegcoreConfig.h SegcoreConfig.cpp)
 add_library(milvus_segcore SHARED
         ${SEGCORE_FILES}
         )
diff --git a/internal/core/src/segcore/FieldIndexing.cpp b/internal/core/src/segcore/FieldIndexing.cpp
index 57c7654c85b8372878dfcafec0f4be0d60f27f34..b44a6594d18a70316d04b8702c75943d9dfea905 100644
--- a/internal/core/src/segcore/FieldIndexing.cpp
+++ b/internal/core/src/segcore/FieldIndexing.cpp
@@ -13,6 +13,8 @@
 #include <thread>
 #include <knowhere/index/vector_index/IndexIVF.h>
 #include <knowhere/index/vector_index/adapter/VectorAdapter.h>
+#include <string>
+#include "common/SystemProperty.h"
 
 namespace milvus::segcore {
 void
@@ -24,7 +26,7 @@ VectorFieldIndexing::BuildIndexRange(int64_t ack_beg, int64_t ack_end, const Vec
     Assert(source);
     auto num_chunk = source->num_chunk();
     assert(ack_end <= num_chunk);
-    auto conf = get_build_conf();
+    auto conf = get_build_params();
     data_.grow_to_at_least(ack_end);
     for (int chunk_id = ack_beg; chunk_id < ack_end; chunk_id++) {
         const auto& chunk = source->get_chunk(chunk_id);
@@ -38,27 +40,37 @@ VectorFieldIndexing::BuildIndexRange(int64_t ack_beg, int64_t ack_end, const Vec
 }
 
 knowhere::Config
-VectorFieldIndexing::get_build_conf() const {
+VectorFieldIndexing::get_build_params() const {
     // TODO
     auto type_opt = field_meta_.get_metric_type();
     Assert(type_opt.has_value());
-    auto type_name = MetricTypeToName(type_opt.value());
-    return knowhere::Config{{knowhere::meta::DIM, field_meta_.get_dim()},
-                            {knowhere::IndexParams::nlist, 100},
-                            {knowhere::IndexParams::nprobe, 4},
-                            {knowhere::Metric::TYPE, type_name},
-                            {knowhere::meta::DEVICEID, 0}};
+    auto metric_type = type_opt.value();
+    auto type_name = MetricTypeToName(metric_type);
+    auto& config = segcore_config_.at(metric_type);
+    auto base_params = config.build_params;
+
+    Assert(base_params.count("nlist"));
+    base_params[knowhere::meta::DIM] = field_meta_.get_dim();
+    base_params[knowhere::Metric::TYPE] = type_name;
+
+    return base_params;
 }
 
 knowhere::Config
-VectorFieldIndexing::get_search_conf(int top_K) const {
+VectorFieldIndexing::get_search_params(int top_K) const {
     // TODO
     auto type_opt = field_meta_.get_metric_type();
     Assert(type_opt.has_value());
-    auto type_name = MetricTypeToName(type_opt.value());
-    return knowhere::Config{{knowhere::meta::DIM, field_meta_.get_dim()}, {knowhere::meta::TOPK, top_K},
-                            {knowhere::IndexParams::nlist, 100},          {knowhere::IndexParams::nprobe, 4},
-                            {knowhere::Metric::TYPE, type_name},          {knowhere::meta::DEVICEID, 0}};
+    auto metric_type = type_opt.value();
+    auto type_name = MetricTypeToName(metric_type);
+    auto& config = segcore_config_.at(metric_type);
+
+    auto base_params = config.search_params;
+    Assert(base_params.count("nprobe"));
+    base_params[knowhere::meta::TOPK] = top_K;
+    base_params[knowhere::Metric::TYPE] = type_name;
+
+    return base_params;
 }
 
 void
@@ -103,10 +115,10 @@ ScalarFieldIndexing<T>::BuildIndexRange(int64_t ack_beg, int64_t ack_end, const
 }
 
 std::unique_ptr<FieldIndexing>
-CreateIndex(const FieldMeta& field_meta, int64_t size_per_chunk) {
+CreateIndex(const FieldMeta& field_meta, const SegcoreConfig& segcore_config) {
     if (field_meta.is_vector()) {
         if (field_meta.get_data_type() == DataType::VECTOR_FLOAT) {
-            return std::make_unique<VectorFieldIndexing>(field_meta, size_per_chunk);
+            return std::make_unique<VectorFieldIndexing>(field_meta, segcore_config);
         } else {
             // TODO
             PanicInfo("unsupported");
@@ -114,19 +126,19 @@ CreateIndex(const FieldMeta& field_meta, int64_t size_per_chunk) {
     }
     switch (field_meta.get_data_type()) {
         case DataType::BOOL:
-            return std::make_unique<ScalarFieldIndexing<bool>>(field_meta, size_per_chunk);
+            return std::make_unique<ScalarFieldIndexing<bool>>(field_meta, segcore_config);
         case DataType::INT8:
-            return std::make_unique<ScalarFieldIndexing<int8_t>>(field_meta, size_per_chunk);
+            return std::make_unique<ScalarFieldIndexing<int8_t>>(field_meta, segcore_config);
         case DataType::INT16:
-            return std::make_unique<ScalarFieldIndexing<int16_t>>(field_meta, size_per_chunk);
+            return std::make_unique<ScalarFieldIndexing<int16_t>>(field_meta, segcore_config);
         case DataType::INT32:
-            return std::make_unique<ScalarFieldIndexing<int32_t>>(field_meta, size_per_chunk);
+            return std::make_unique<ScalarFieldIndexing<int32_t>>(field_meta, segcore_config);
         case DataType::INT64:
-            return std::make_unique<ScalarFieldIndexing<int64_t>>(field_meta, size_per_chunk);
+            return std::make_unique<ScalarFieldIndexing<int64_t>>(field_meta, segcore_config);
         case DataType::FLOAT:
-            return std::make_unique<ScalarFieldIndexing<float>>(field_meta, size_per_chunk);
+            return std::make_unique<ScalarFieldIndexing<float>>(field_meta, segcore_config);
         case DataType::DOUBLE:
-            return std::make_unique<ScalarFieldIndexing<double>>(field_meta, size_per_chunk);
+            return std::make_unique<ScalarFieldIndexing<double>>(field_meta, segcore_config);
         default:
             PanicInfo("unsupported");
     }
diff --git a/internal/core/src/segcore/FieldIndexing.h b/internal/core/src/segcore/FieldIndexing.h
index be15ff556271267df78f4b32ab329a531ac422eb..bb7f41c51e9fafb0df0b52162992b5277871c08f 100644
--- a/internal/core/src/segcore/FieldIndexing.h
+++ b/internal/core/src/segcore/FieldIndexing.h
@@ -19,6 +19,7 @@
 #include "InsertRecord.h"
 #include <knowhere/index/vector_index/IndexIVF.h>
 #include <knowhere/index/structured_index_simple/StructuredIndexSort.h>
+#include "segcore/SegcoreConfig.h"
 
 namespace milvus::segcore {
 
@@ -26,8 +27,8 @@ namespace milvus::segcore {
 // All concurrent
 class FieldIndexing {
  public:
-    explicit FieldIndexing(const FieldMeta& field_meta, int64_t size_per_chunk)
-        : field_meta_(field_meta), size_per_chunk_(size_per_chunk) {
+    explicit FieldIndexing(const FieldMeta& field_meta, const SegcoreConfig& segcore_config)
+        : field_meta_(field_meta), segcore_config_(segcore_config) {
     }
     FieldIndexing(const FieldIndexing&) = delete;
     FieldIndexing&
@@ -44,7 +45,7 @@ class FieldIndexing {
 
     int64_t
     get_size_per_chunk() const {
-        return size_per_chunk_;
+        return segcore_config_.get_size_per_chunk();
     }
 
     virtual knowhere::Index*
@@ -53,7 +54,7 @@ class FieldIndexing {
  protected:
     // additional info
     const FieldMeta& field_meta_;
-    const int64_t size_per_chunk_;
+    const SegcoreConfig& segcore_config_;
 };
 template <typename T>
 class ScalarFieldIndexing : public FieldIndexing {
@@ -89,21 +90,22 @@ class VectorFieldIndexing : public FieldIndexing {
     }
 
     knowhere::Config
-    get_build_conf() const;
+    get_build_params() const;
+
     knowhere::Config
-    get_search_conf(int top_k) const;
+    get_search_params(int top_k) const;
 
  private:
     tbb::concurrent_vector<std::unique_ptr<knowhere::VecIndex>> data_;
 };
 
 std::unique_ptr<FieldIndexing>
-CreateIndex(const FieldMeta& field_meta, int64_t size_per_chunk);
+CreateIndex(const FieldMeta& field_meta, const SegcoreConfig& segcore_config);
 
 class IndexingRecord {
  public:
-    explicit IndexingRecord(const Schema& schema, int64_t size_per_chunk)
-        : schema_(schema), size_per_chunk_(size_per_chunk) {
+    explicit IndexingRecord(const Schema& schema, const SegcoreConfig& segcore_config)
+        : schema_(schema), segcore_config_(segcore_config) {
         Initialize();
     }
 
@@ -125,7 +127,7 @@ class IndexingRecord {
                 }
             }
 
-            field_indexings_.try_emplace(offset, CreateIndex(field, size_per_chunk_));
+            field_indexings_.try_emplace(offset, CreateIndex(field, segcore_config_));
         }
         assert(offset_id == schema_.size());
     }
@@ -170,6 +172,7 @@ class IndexingRecord {
 
  private:
     const Schema& schema_;
+    const SegcoreConfig& segcore_config_;
 
  private:
     // control info
@@ -177,7 +180,6 @@ class IndexingRecord {
     //    std::atomic<int64_t> finished_ack_ = 0;
     AckResponder finished_ack_;
     std::mutex mutex_;
-    int64_t size_per_chunk_;
 
  private:
     // field_offset => indexing
diff --git a/internal/core/src/segcore/SegcoreConfig.cpp b/internal/core/src/segcore/SegcoreConfig.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..e7808e9da8d6d86fcaa2a40652b15c0680c81a58
--- /dev/null
+++ b/internal/core/src/segcore/SegcoreConfig.cpp
@@ -0,0 +1,107 @@
+// Copyright (C) 2019-2020 Zilliz. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software distributed under the License
+// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+// or implied. See the License for the specific language governing permissions and limitations under the License
+
+#include "common/Schema.h"
+#include "SegcoreConfig.h"
+#include "utils/Json.h"
+#include "yaml-cpp/yaml.h"
+
+namespace milvus::segcore {
+
+static YAML::Node
+subnode(const YAML::Node& parent, const std::string& key) {
+    AssertInfo(parent.IsMap(), "wrong type node when getting key[" + key + "]");
+    auto& node = parent[key];
+    AssertInfo(node.IsDefined(), "key[" + key + "] not found in sub-node");
+    return node;
+}
+
+template <typename T, typename Func>
+std::vector<T>
+apply_parser(const YAML::Node& node, Func func) {
+    std::vector<T> results;
+    Assert(node.IsDefined());
+    if (node.IsScalar()) {
+        results.emplace_back(func(node));
+    } else if (node.IsSequence()) {
+        for (auto& element : node) {
+            Assert(element.IsScalar());
+            results.emplace_back(func(element));
+        }
+    } else {
+        PanicInfo("node should be scalar or sequence");
+    }
+    return results;
+}
+
+SegcoreConfig
+SegcoreConfig::parse_from(const std::string& config_path) {
+    try {
+        SegcoreConfig result;
+        YAML::Node top_config = YAML::LoadFile(config_path);
+        Assert(top_config.IsMap());
+        auto seg_config = subnode(top_config, "segcore");
+        auto chunk_size = subnode(seg_config, "chunk_size").as<int64_t>();
+        result.size_per_chunk_ = chunk_size;
+
+        auto index_list = subnode(seg_config, "small_index");
+
+        Assert(index_list.IsSequence());
+        for (auto index : index_list) {
+            Assert(index.IsMap());
+            auto metric_types = apply_parser<MetricType>(subnode(index, "metric_type"), [](const YAML::Node& node) {
+                return GetMetricType(node.as<std::string>());
+            });
+
+            {
+                std::sort(metric_types.begin(), metric_types.end());
+                auto end_iter = std::unique(metric_types.begin(), metric_types.end());
+                metric_types.resize(end_iter - metric_types.begin());
+            }
+
+            auto index_type = index["index_type"].as<std::string>();
+            AssertInfo(index_type == "IVF", "only ivf is supported now");
+
+            SmallIndexConf conf;
+            conf.index_type = index_type;
+
+            // parse build config
+            for (auto node : index["build_params"]) {
+                // TODO: currently support IVF only
+                auto key = node.first.as<std::string>();
+                Assert(key == "nlist");
+                auto value = node.second.as<int64_t>();
+                conf.build_params[key] = value;
+            }
+
+            // parse search config
+            for (auto node : index["search_params"]) {
+                // TODO: currently support IVF only
+                auto key = node.first.as<std::string>();
+                Assert(key == "nprobe");
+                auto value = node.second.as<int64_t>();
+                conf.search_params[key] = value;
+            }
+
+            for (auto metric_type : metric_types) {
+                Assert(result.table_.count(metric_type));
+                result.table_[metric_type] = conf;
+            }
+        }
+    } catch (const WrappedRuntimeError& e) {
+        // re-throw
+        throw e;
+    } catch (std::exception& e) {
+        PanicInfo(std::string("Invalid Yaml:\n") + e.what());
+    }
+}
+
+}  // namespace milvus::segcore
diff --git a/internal/core/src/segcore/SegcoreConfig.h b/internal/core/src/segcore/SegcoreConfig.h
new file mode 100644
index 0000000000000000000000000000000000000000..21cd0414a34325133814de9e48074e33b751ee00
--- /dev/null
+++ b/internal/core/src/segcore/SegcoreConfig.h
@@ -0,0 +1,73 @@
+// Copyright (C) 2019-2020 Zilliz. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software distributed under the License
+// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+// or implied. See the License for the specific language governing permissions and limitations under the License
+
+#pragma once
+#include "common/Types.h"
+#include "utils/Json.h"
+#include <map>
+#include <string>
+
+namespace milvus::segcore {
+
+struct SmallIndexConf {
+    std::string index_type;
+    nlohmann::json build_params;
+    nlohmann::json search_params;
+};
+
+class SegcoreConfig {
+ public:
+    static SegcoreConfig
+    parse_from(const std::string& string_path);
+    static SegcoreConfig
+    default_config() {
+        // TODO: remove this when go side is ready
+        SegcoreConfig config;
+        config.set_size_per_chunk(32 * 1024);
+        SmallIndexConf sub_conf;
+        sub_conf.build_params["nlist"] = 100;
+        sub_conf.search_params["nprobe"] = 4;
+        sub_conf.index_type = "IVF";
+        config.table_[MetricType::METRIC_L2] = sub_conf;
+        config.table_[MetricType::METRIC_INNER_PRODUCT] = sub_conf;
+        return config;
+    }
+
+    const SmallIndexConf&
+    at(MetricType metric_type) const {
+        Assert(table_.count(metric_type));
+        return table_.at(metric_type);
+    }
+
+    int64_t
+    get_size_per_chunk() const {
+        return size_per_chunk_;
+    }
+
+    void
+    set_size_per_chunk(int64_t size_per_chunk) {
+        size_per_chunk_ = size_per_chunk;
+    }
+
+    void
+    set_small_index_config(MetricType metric_type, const SmallIndexConf& small_index_conf) {
+        table_[metric_type] = small_index_conf;
+    }
+
+ protected:
+    SegcoreConfig() = default;
+
+ private:
+    int64_t size_per_chunk_ = -1;
+    std::map<MetricType, SmallIndexConf> table_;
+};
+
+}  // namespace milvus::segcore
diff --git a/internal/core/src/segcore/SegmentGrowing.cpp b/internal/core/src/segcore/SegmentGrowing.cpp
index 0d51d8abb26fbc69398db419ef31e721c1b33214..bdc1fc6421c3b24b1cb6bdc6611898e9ca4217ae 100644
--- a/internal/core/src/segcore/SegmentGrowing.cpp
+++ b/internal/core/src/segcore/SegmentGrowing.cpp
@@ -20,8 +20,8 @@ TestABI() {
 }
 
 std::unique_ptr<SegmentGrowing>
-CreateGrowingSegment(SchemaPtr schema, int64_t size_per_chunk) {
-    auto segment = std::make_unique<SegmentGrowingImpl>(schema, size_per_chunk);
+CreateGrowingSegment(SchemaPtr schema, const SegcoreConfig& segcore_config) {
+    auto segment = std::make_unique<SegmentGrowingImpl>(schema, segcore_config);
     return segment;
 }
 
diff --git a/internal/core/src/segcore/SegmentGrowing.h b/internal/core/src/segcore/SegmentGrowing.h
index 6cc5f11b11c0954fa1c154547bdb6fa75962cbf8..d24be928636d59f7bcabff4cfe7ef586ae1df17a 100644
--- a/internal/core/src/segcore/SegmentGrowing.h
+++ b/internal/core/src/segcore/SegmentGrowing.h
@@ -95,7 +95,13 @@ class SegmentGrowing : public SegmentInternalInterface {
 using SegmentGrowingPtr = std::unique_ptr<SegmentGrowing>;
 
 SegmentGrowingPtr
-CreateGrowingSegment(SchemaPtr schema, int64_t size_per_chunk = 32 * 1024);
+CreateGrowingSegment(SchemaPtr schema, const SegcoreConfig& segcore_config);
+
+inline SegmentGrowingPtr
+CreateGrowingSegment(SchemaPtr schema) {
+    auto seg_conf = SegcoreConfig::default_config();
+    return CreateGrowingSegment(schema, seg_conf);
+}
 
 }  // namespace segcore
 }  // namespace milvus
diff --git a/internal/core/src/segcore/SegmentGrowingImpl.cpp b/internal/core/src/segcore/SegmentGrowingImpl.cpp
index b6dd81795718c304e3451ae85cdb24dc4bcb6cc7..ae311d93d2ed695efa26eafa1e1e1a47e02a0759 100644
--- a/internal/core/src/segcore/SegmentGrowingImpl.cpp
+++ b/internal/core/src/segcore/SegmentGrowingImpl.cpp
@@ -190,7 +190,8 @@ SegmentGrowingImpl::do_insert(int64_t reserved_begin,
     }
     record_.ack_responder_.AddSegment(reserved_begin, reserved_begin + size);
     if (!debug_disable_small_index_) {
-        indexing_record_.UpdateResourceAck(record_.ack_responder_.GetAck() / size_per_chunk_, record_);
+        indexing_record_.UpdateResourceAck(record_.ack_responder_.GetAck() / segcore_config_.get_size_per_chunk(),
+                                           record_);
     }
 }
 
@@ -241,9 +242,10 @@ SegmentGrowingImpl::Close() {
 int64_t
 SegmentGrowingImpl::GetMemoryUsageInBytes() const {
     int64_t total_bytes = 0;
-    int64_t ins_n = upper_align(record_.reserved, size_per_chunk_);
+    auto size_per_chunk = segcore_config_.get_size_per_chunk();
+    int64_t ins_n = upper_align(record_.reserved, size_per_chunk);
     total_bytes += ins_n * (schema_->get_total_sizeof() + 16 + 1);
-    int64_t del_n = upper_align(deleted_record_.reserved, size_per_chunk_);
+    int64_t del_n = upper_align(deleted_record_.reserved, size_per_chunk);
     total_bytes += del_n * (16 * 2);
     return total_bytes;
 }
@@ -268,7 +270,7 @@ SegmentGrowingImpl::chunk_data_impl(FieldOffset field_offset, int64_t chunk_id)
 int64_t
 SegmentGrowingImpl::num_chunk() const {
     auto size = get_insert_record().ack_responder_.GetAck();
-    return upper_div(size, size_per_chunk_);
+    return upper_div(size, segcore_config_.get_size_per_chunk());
 }
 void
 SegmentGrowingImpl::vector_search(int64_t vec_count,
diff --git a/internal/core/src/segcore/SegmentGrowingImpl.h b/internal/core/src/segcore/SegmentGrowingImpl.h
index 7a62a8edee6e2e44d9debca35666f4865b207dc7..25ea5162e055af81635da4788a1e6b3dd100e702 100644
--- a/internal/core/src/segcore/SegmentGrowingImpl.h
+++ b/internal/core/src/segcore/SegmentGrowingImpl.h
@@ -108,7 +108,7 @@ class SegmentGrowingImpl : public SegmentGrowing {
 
     int64_t
     size_per_chunk() const final {
-        return size_per_chunk_;
+        return segcore_config_.get_size_per_chunk();
     }
 
  public:
@@ -157,13 +157,13 @@ class SegmentGrowingImpl : public SegmentGrowing {
 
  public:
     friend std::unique_ptr<SegmentGrowing>
-    CreateGrowingSegment(SchemaPtr schema, int64_t size_per_chunk);
+    CreateGrowingSegment(SchemaPtr schema, const SegcoreConfig& segcore_config);
 
-    explicit SegmentGrowingImpl(SchemaPtr schema, int64_t size_per_chunk)
-        : size_per_chunk_(size_per_chunk),
+    explicit SegmentGrowingImpl(SchemaPtr schema, const SegcoreConfig& segcore_config)
+        : segcore_config_(segcore_config),
           schema_(std::move(schema)),
-          record_(*schema_, size_per_chunk),
-          indexing_record_(*schema_, size_per_chunk) {
+          record_(*schema_, segcore_config.get_size_per_chunk()),
+          indexing_record_(*schema_, segcore_config_) {
     }
 
     void
@@ -199,7 +199,7 @@ class SegmentGrowingImpl : public SegmentGrowing {
               const std::vector<aligned_vector<uint8_t>>& columns_data);
 
  private:
-    int64_t size_per_chunk_;
+    SegcoreConfig segcore_config_;
     SchemaPtr schema_;
     std::atomic<SegmentState> state_ = SegmentState::Open;
 
diff --git a/internal/core/src/segcore/SegmentSealed.h b/internal/core/src/segcore/SegmentSealed.h
index b532fe9cde495a32cf71f78b4c2b3a2f85d0a360..8afeadd59548565ef85c001c39d79568099c05c0 100644
--- a/internal/core/src/segcore/SegmentSealed.h
+++ b/internal/core/src/segcore/SegmentSealed.h
@@ -35,6 +35,6 @@ class SegmentSealed : public SegmentInternalInterface {
 using SegmentSealedPtr = std::unique_ptr<SegmentSealed>;
 
 SegmentSealedPtr
-CreateSealedSegment(SchemaPtr schema, int64_t size_per_chunk = 32 * 1024);
+CreateSealedSegment(SchemaPtr schema);
 
 }  // namespace milvus::segcore
diff --git a/internal/core/src/segcore/SegmentSealedImpl.cpp b/internal/core/src/segcore/SegmentSealedImpl.cpp
index 769e3e086769fcf3e097955fca5d1f1f7e679df4..279352dfec26596ea87db8b3430015a419793955 100644
--- a/internal/core/src/segcore/SegmentSealedImpl.cpp
+++ b/internal/core/src/segcore/SegmentSealedImpl.cpp
@@ -384,7 +384,7 @@ SegmentSealedImpl::HasFieldData(FieldId field_id) const {
 }
 
 SegmentSealedPtr
-CreateSealedSegment(SchemaPtr schema, int64_t size_per_chunk) {
+CreateSealedSegment(SchemaPtr schema) {
     return std::make_unique<SegmentSealedImpl>(schema);
 }
 
diff --git a/internal/core/src/utils/EasyAssert.cpp b/internal/core/src/utils/EasyAssert.cpp
index ae74724f53cf045b5198f4ceaeb85ae42e7ef798..1bc4506d668fedd03571b33cb94b64447f6bd762 100644
--- a/internal/core/src/utils/EasyAssert.cpp
+++ b/internal/core/src/utils/EasyAssert.cpp
@@ -46,11 +46,11 @@ EasyAssertInfo(
 
 [[noreturn]] void
 ThrowWithTrace(const std::exception& exception) {
-    if (typeid(exception) == typeid(WrappedRuntimError)) {
+    if (typeid(exception) == typeid(WrappedRuntimeError)) {
         throw exception;
     }
     auto err_msg = exception.what() + std::string("\n") + EasyStackTrace();
-    throw WrappedRuntimError(err_msg);
+    throw WrappedRuntimeError(err_msg);
 }
 
 }  // namespace milvus::impl
diff --git a/internal/core/src/utils/EasyAssert.h b/internal/core/src/utils/EasyAssert.h
index 8ef54042d7530665686065c0306b8d41e1d8ae16..bf5f5ca729a8658e270f0c952250c4ebd3e90a75 100644
--- a/internal/core/src/utils/EasyAssert.h
+++ b/internal/core/src/utils/EasyAssert.h
@@ -18,19 +18,22 @@
 
 /* Paste this on the file you want to debug. */
 
-namespace milvus::impl {
+namespace milvus {
+namespace impl {
 void
 EasyAssertInfo(
     bool value, std::string_view expr_str, std::string_view filename, int lineno, std::string_view extra_info);
 
-class WrappedRuntimError : public std::runtime_error {
-    using std::runtime_error::runtime_error;
-};
-
 [[noreturn]] void
 ThrowWithTrace(const std::exception& exception);
 
-}  // namespace milvus::impl
+}  // namespace impl
+
+class WrappedRuntimeError : public std::runtime_error {
+    using std::runtime_error::runtime_error;
+};
+
+}  // namespace milvus
 
 #define AssertInfo(expr, info)                                                          \
     do {                                                                                \
diff --git a/internal/core/thirdparty/CMakeLists.txt b/internal/core/thirdparty/CMakeLists.txt
index 787d7e6535271096c6cd532ae70455d23aa8a607..7098c2e351ebede29503261bd77d85b8baf58eef 100644
--- a/internal/core/thirdparty/CMakeLists.txt
+++ b/internal/core/thirdparty/CMakeLists.txt
@@ -46,9 +46,7 @@ endif()
 
 
 # ****************************** Thirdparty yaml ***************************************
-if ( MILVUS_WITH_YAMLCPP )
-    add_subdirectory( yaml-cpp )
-endif()
+add_subdirectory( yaml-cpp )
 
 # ****************************** Thirdparty opentracing ***************************************
 if ( MILVUS_WITH_OPENTRACING )
diff --git a/internal/core/unittest/CMakeLists.txt b/internal/core/unittest/CMakeLists.txt
index 51bc740e6e0b054a4f78c1a2481bca73074e1da6..edf8669ba44ec2133b0a4c52191ac14e495b22d2 100644
--- a/internal/core/unittest/CMakeLists.txt
+++ b/internal/core/unittest/CMakeLists.txt
@@ -1,5 +1,9 @@
 include_directories(${CMAKE_HOME_DIRECTORY}/src)
 include_directories(${CMAKE_HOME_DIRECTORY}/src/index/knowhere)
+include_directories(${CMAKE_HOME_DIRECTORY}/src/thirdparty)
+
+add_definitions(-DMILVUS_TEST_SEGCORE_YAML_PATH="${CMAKE_SOURCE_DIR}/unittest/test_utils/test_segcore.yaml")
+
 set(MILVUS_TEST_FILES
         test_naive.cpp
         test_segcore.cpp
@@ -17,14 +21,18 @@ set(MILVUS_TEST_FILES
         test_interface.cpp
         test_span.cpp
         test_load.cpp
+        init_gtest.cpp
         )
+
 add_executable(all_tests
         ${MILVUS_TEST_FILES}
         )
 
 # check if memory leak exists in index builder
 set(INDEX_BUILDER_TEST_FILES
-        test_index_wrapper.cpp)
+        test_index_wrapper.cpp
+        )
+
 add_executable(index_builder_test
         ${INDEX_BUILDER_TEST_FILES}
         )
@@ -39,7 +47,6 @@ target_link_libraries(index_builder_test
 
 target_link_libraries(all_tests
         gtest
-        gtest_main
         milvus_segcore
         milvus_indexbuilder
         log
diff --git a/internal/core/unittest/init_gtest.cpp b/internal/core/unittest/init_gtest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..dd6578404fb51cd0513844269e9bdd55b8789454
--- /dev/null
+++ b/internal/core/unittest/init_gtest.cpp
@@ -0,0 +1,24 @@
+// Copyright (C) 2019-2020 Zilliz. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software distributed under the License
+// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+// or implied. See the License for the specific language governing permissions and limitations under the License
+
+#include <gtest/gtest.h>
+#include "common/SystemProperty.h"
+#ifndef MILVUS_TEST_SEGCORE_YAML_PATH
+#error MILVUS_TEST_SEGCORE_YAML_PATH is not defined
+#define MILVUS_TEST_SEGCORE_YAML_PATH ""
+#endif
+
+int
+main(int argc, char** argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+
+    return RUN_ALL_TESTS();
+}
\ No newline at end of file
diff --git a/internal/core/unittest/test_span.cpp b/internal/core/unittest/test_span.cpp
index 8c582f344c97e878660f3f3f3899be517d2df32f..9c21e45d0b0a0d61ba653bab23c31e80a1355f5b 100644
--- a/internal/core/unittest/test_span.cpp
+++ b/internal/core/unittest/test_span.cpp
@@ -26,7 +26,8 @@ TEST(Span, Naive) {
     schema->AddDebugField("floatvec", DataType::VECTOR_FLOAT, 32, MetricType::METRIC_L2);
 
     auto dataset = DataGen(schema, N);
-    auto segment = CreateGrowingSegment(schema, size_per_chunk);
+    auto seg_conf = SegcoreConfig::default_config();
+    auto segment = CreateGrowingSegment(schema, seg_conf);
     segment->PreInsert(N);
     segment->Insert(0, N, dataset.row_ids_.data(), dataset.timestamps_.data(), dataset.raw_);
     auto vec_ptr = dataset.get_col<uint8_t>(0);
diff --git a/internal/core/unittest/test_utils/test_segcore.yaml b/internal/core/unittest/test_utils/test_segcore.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..cdad64f22df812b5a0cef1efd641e0b179d35abb
--- /dev/null
+++ b/internal/core/unittest/test_utils/test_segcore.yaml
@@ -0,0 +1,16 @@
+segcore:
+  chunk_size: 32768
+  small_index:
+    - metric_type: ["L2", "IP"]
+      index_type: "IVF"
+      build_params:
+        nlist: 100
+      search_params:
+        nprobe: 4
+    # binary is not ready yet
+    - metric_type: ["jaccard"]
+      index_type: "IVF"
+      build_params:
+        nlist: 100
+      search_params:
+        nprobe: 4