diff --git a/internal/core/src/indexbuilder/IndexWrapper.cpp b/internal/core/src/indexbuilder/IndexWrapper.cpp
index cb53d66bfd94a40d6759f42bf12b0ca74d6287f4..f06c349cf26f0a0e5274b4eaabc2a90d7bcef4fa 100644
--- a/internal/core/src/indexbuilder/IndexWrapper.cpp
+++ b/internal/core/src/indexbuilder/IndexWrapper.cpp
@@ -9,6 +9,9 @@
 // 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 <map>
+#include <exception>
+
 #include "pb/index_cgo_msg.pb.h"
 #include "knowhere/index/vector_index/VecIndexFactory.h"
 #include "knowhere/index/vector_index/helpers/IndexParameter.h"
@@ -24,11 +27,14 @@ IndexWrapper::IndexWrapper(const char* serialized_type_params, const char* seria
 
     parse();
 
-    auto index_type = index_config_["index_type"].get<std::string>();
-    auto index_mode = index_config_["index_mode"].get<std::string>();
-    auto mode = index_mode == "CPU" ? knowhere::IndexMode::MODE_CPU : knowhere::IndexMode::MODE_GPU;
+    std::map<std::string, knowhere::IndexMode> mode_map = {{"CPU", knowhere::IndexMode::MODE_CPU},
+                                                           {"GPU", knowhere::IndexMode::MODE_GPU}};
+    auto type = get_config_by_name<std::string>("index_type");
+    auto mode = get_config_by_name<std::string>("index_mode");
+    auto index_type = type.has_value() ? type.value() : knowhere::IndexEnum::INDEX_FAISS_IVFPQ;
+    auto index_mode = mode.has_value() ? mode_map[mode.value()] : knowhere::IndexMode::MODE_CPU;
 
-    index_ = knowhere::VecIndexFactory::GetInstance().CreateVecIndex(index_type, mode);
+    index_ = knowhere::VecIndexFactory::GetInstance().CreateVecIndex(index_type, index_mode);
 }
 
 void
@@ -36,38 +42,90 @@ IndexWrapper::parse() {
     namespace indexcgo = milvus::proto::indexcgo;
     bool serialized_success;
 
-    indexcgo::BinarySet type_config;
+    indexcgo::TypeParams type_config;
     serialized_success = type_config.ParseFromString(type_params_);
     Assert(serialized_success);
 
-    indexcgo::BinarySet index_config;
+    indexcgo::IndexParams index_config;
     serialized_success = index_config.ParseFromString(index_params_);
     Assert(serialized_success);
 
-    for (auto i = 0; i < type_config.datas_size(); ++i) {
-        auto binary = type_config.datas(i);
-        type_config_[binary.key()] = binary.value();
+    for (auto i = 0; i < type_config.params_size(); ++i) {
+        auto type_param = type_config.params(i);
+        auto key = type_param.key();
+        auto value = type_param.value();
+        type_config_[key] = value;
+        config_[key] = value;
+    }
+
+    for (auto i = 0; i < index_config.params_size(); ++i) {
+        auto index_param = index_config.params(i);
+        auto key = index_param.key();
+        auto value = index_param.value();
+        index_config_[key] = value;
+        config_[key] = value;
+    }
+
+    if (!config_.contains(milvus::knowhere::meta::DIM)) {
+        // should raise exception here?
+        throw "dim must be specific in type params or index params!";
+    } else {
+        auto dim = config_[milvus::knowhere::meta::DIM].get<std::string>();
+        config_[milvus::knowhere::meta::DIM] = std::stoi(dim);
+    }
+
+    if (!config_.contains(milvus::knowhere::meta::TOPK)) {
+    } else {
+        auto topk = config_[milvus::knowhere::meta::TOPK].get<std::string>();
+        config_[milvus::knowhere::meta::TOPK] = std::stoi(topk);
+    }
+
+    if (!config_.contains(milvus::knowhere::IndexParams::nlist)) {
+    } else {
+        auto nlist = config_[milvus::knowhere::IndexParams::nlist].get<std::string>();
+        config_[milvus::knowhere::IndexParams::nlist] = std::stoi(nlist);
     }
 
-    for (auto i = 0; i < index_config.datas_size(); ++i) {
-        auto binary = index_config.datas(i);
-        index_config_[binary.key()] = binary.value();
+    if (!config_.contains(milvus::knowhere::IndexParams::nprobe)) {
+    } else {
+        auto nprobe = config_[milvus::knowhere::IndexParams::nprobe].get<std::string>();
+        config_[milvus::knowhere::IndexParams::nprobe] = std::stoi(nprobe);
     }
 
-    // TODO: parse from type_params & index_params
-    auto dim = 128;
-    config_ = knowhere::Config{
-        {knowhere::meta::DIM, dim},         {knowhere::IndexParams::nlist, 100},
-        {knowhere::IndexParams::nprobe, 4}, {knowhere::IndexParams::m, 4},
-        {knowhere::IndexParams::nbits, 8},  {knowhere::Metric::TYPE, knowhere::Metric::L2},
-        {knowhere::meta::DEVICEID, 0},
-    };
+    if (!config_.contains(milvus::knowhere::IndexParams::nbits)) {
+    } else {
+        auto nbits = config_[milvus::knowhere::IndexParams::nbits].get<std::string>();
+        config_[milvus::knowhere::IndexParams::nbits] = std::stoi(nbits);
+    }
+
+    if (!config_.contains(milvus::knowhere::IndexParams::m)) {
+    } else {
+        auto m = config_[milvus::knowhere::IndexParams::m].get<std::string>();
+        config_[milvus::knowhere::IndexParams::m] = std::stoi(m);
+    }
+
+    if (!config_.contains(milvus::knowhere::INDEX_FILE_SLICE_SIZE_IN_MEGABYTE)) {
+        config_[milvus::knowhere::INDEX_FILE_SLICE_SIZE_IN_MEGABYTE] = 4;
+    } else {
+        auto slice_size = config_[milvus::knowhere::INDEX_FILE_SLICE_SIZE_IN_MEGABYTE].get<std::string>();
+        config_[milvus::knowhere::INDEX_FILE_SLICE_SIZE_IN_MEGABYTE] = std::stoi(slice_size);
+    }
+}
+
+template <typename T>
+std::optional<T>
+IndexWrapper::get_config_by_name(std::string name) {
+    if (config_.contains(name)) {
+        return {config_[name].get<T>()};
+    }
+    return std::nullopt;
 }
 
 int64_t
 IndexWrapper::dim() {
-    // TODO: get from config
-    return 128;
+    auto dimension = get_config_by_name<int64_t>(milvus::knowhere::meta::DIM);
+    Assert(dimension.has_value());
+    return (dimension.value());
 }
 
 void
@@ -88,24 +146,23 @@ IndexWrapper::Serialize() {
     for (auto [key, value] : binarySet.binary_map_) {
         auto binary = ret.add_datas();
         binary->set_key(key);
-        binary->set_value(reinterpret_cast<char*>(value->data.get()));
+        binary->set_value(value->data.get(), value->size);
     }
 
     std::string serialized_data;
     auto ok = ret.SerializeToString(&serialized_data);
     Assert(ok);
 
-    auto data = new char[serialized_data.length() + 1];
+    auto data = new char[serialized_data.length()];
     memcpy(data, serialized_data.c_str(), serialized_data.length());
-    data[serialized_data.length()] = 0;
 
-    return {data, static_cast<int32_t>(serialized_data.length() + 1)};
+    return {data, static_cast<int32_t>(serialized_data.length())};
 }
 
 void
-IndexWrapper::Load(const char* serialized_sliced_blob_buffer) {
+IndexWrapper::Load(const char* serialized_sliced_blob_buffer, int32_t size) {
     namespace indexcgo = milvus::proto::indexcgo;
-    auto data = std::string(serialized_sliced_blob_buffer);
+    auto data = std::string(serialized_sliced_blob_buffer, size);
     indexcgo::BinarySet blob_buffer;
 
     auto ok = blob_buffer.ParseFromString(data);
diff --git a/internal/core/src/indexbuilder/IndexWrapper.h b/internal/core/src/indexbuilder/IndexWrapper.h
index ab326fc2eafe77db6738712d54ade3eda806f4ca..49954cc209e83d95af803a72654e3233b63f500d 100644
--- a/internal/core/src/indexbuilder/IndexWrapper.h
+++ b/internal/core/src/indexbuilder/IndexWrapper.h
@@ -10,6 +10,7 @@
 // or implied. See the License for the specific language governing permissions and limitations under the License
 
 #include <string>
+#include <optional>
 #include "knowhere/index/vector_index/VecIndex.h"
 
 namespace milvus {
@@ -34,12 +35,16 @@ class IndexWrapper {
     Serialize();
 
     void
-    Load(const char* serialized_sliced_blob_buffer);
+    Load(const char* serialized_sliced_blob_buffer, int32_t size);
 
  private:
     void
     parse();
 
+    template <typename T>
+    std::optional<T>
+    get_config_by_name(std::string name);
+
  private:
     knowhere::VecIndexPtr index_ = nullptr;
     std::string type_params_;
diff --git a/internal/core/src/indexbuilder/index_c.cpp b/internal/core/src/indexbuilder/index_c.cpp
index 29a52526296e9e0e8e9d4e06697caf6de65e9330..51e4a9cf461126589425a2d1ba7044f3f893ec85 100644
--- a/internal/core/src/indexbuilder/index_c.cpp
+++ b/internal/core/src/indexbuilder/index_c.cpp
@@ -18,7 +18,7 @@ CIndex
 CreateIndex(const char* serialized_type_params, const char* serialized_index_params) {
     auto index = std::make_unique<milvus::indexbuilder::IndexWrapper>(serialized_type_params, serialized_index_params);
 
-    return (void*)(index.release());
+    return index.release();
 }
 
 void
@@ -45,7 +45,7 @@ SerializeToSlicedBuffer(CIndex index, int32_t* buffer_size) {
 }
 
 void
-LoadFromSlicedBuffer(CIndex index, const char* serialized_sliced_blob_buffer) {
+LoadFromSlicedBuffer(CIndex index, const char* serialized_sliced_blob_buffer, int32_t size) {
     auto cIndex = (milvus::indexbuilder::IndexWrapper*)index;
-    cIndex->Load(serialized_sliced_blob_buffer);
+    cIndex->Load(serialized_sliced_blob_buffer, size);
 }
diff --git a/internal/core/src/indexbuilder/index_c.h b/internal/core/src/indexbuilder/index_c.h
index 6918c8743ae2f184c5101d422c0f263ff17c5d2d..128bdc8ac2bf6a41ab7992c522e2f77d919275ef 100644
--- a/internal/core/src/indexbuilder/index_c.h
+++ b/internal/core/src/indexbuilder/index_c.h
@@ -47,7 +47,7 @@ char*
 SerializeToSlicedBuffer(CIndex index, int32_t* buffer_size);
 
 void
-LoadFromSlicedBuffer(CIndex index, const char* serialized_sliced_blob_buffer);
+LoadFromSlicedBuffer(CIndex index, const char* serialized_sliced_blob_buffer, int32_t size);
 
 #ifdef __cplusplus
 };
diff --git a/internal/core/unittest/CMakeLists.txt b/internal/core/unittest/CMakeLists.txt
index 29fef50fb70a9c26b49e4f1f5b7d573d1263049f..afef74785ec502cabf8663c3c06d74516cd244e0 100644
--- a/internal/core/unittest/CMakeLists.txt
+++ b/internal/core/unittest/CMakeLists.txt
@@ -12,6 +12,7 @@ set(MILVUS_TEST_FILES
         test_expr.cpp
         test_bitmap.cpp 
         test_binary.cpp
+        test_index_wrapper.cpp
         )
 add_executable(all_tests
         ${MILVUS_TEST_FILES}
@@ -21,6 +22,7 @@ target_link_libraries(all_tests
         gtest
         gtest_main
         milvus_segcore
+        milvus_indexbuilder
         knowhere
         log
         pthread
diff --git a/internal/core/unittest/test_index_wrapper.cpp b/internal/core/unittest/test_index_wrapper.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..635950a76acb756d154000f83e912d50b49e5b02
--- /dev/null
+++ b/internal/core/unittest/test_index_wrapper.cpp
@@ -0,0 +1,168 @@
+// 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 <tuple>
+#include <random>
+#include <gtest/gtest.h>
+
+#include "pb/index_cgo_msg.pb.h"
+#include "index/knowhere/knowhere/index/vector_index/helpers/IndexParameter.h"
+#include "index/knowhere/knowhere/index/vector_index/adapter/VectorAdapter.h"
+#include "indexbuilder/IndexWrapper.h"
+#include "indexbuilder/index_c.h"
+#include "test_utils/DataGen.h"
+#include "faiss/MetricType.h"
+#include "index/knowhere/knowhere/index/vector_index/VecIndexFactory.h"
+
+namespace indexcgo = milvus::proto::indexcgo;
+
+constexpr int64_t DIM = 4;
+constexpr int64_t NB = 10000;
+constexpr int64_t NQ = 10;
+constexpr int64_t K = 4;
+constexpr auto METRIC_TYPE = milvus::knowhere::Metric::L2;
+
+namespace {
+auto
+generate_conf(const milvus::knowhere::IndexType& type) {
+    if (type == milvus::knowhere::IndexEnum::INDEX_FAISS_IVFPQ) {
+        return milvus::knowhere::Config{
+            {milvus::knowhere::meta::DIM, DIM},
+            {milvus::knowhere::meta::TOPK, K},
+            {milvus::knowhere::IndexParams::nlist, 100},
+            // {milvus::knowhere::IndexParams::nprobe, 4},
+            {milvus::knowhere::IndexParams::m, 4},
+            {milvus::knowhere::IndexParams::nbits, 8},
+            {milvus::knowhere::Metric::TYPE, milvus::knowhere::Metric::L2},
+            {milvus::knowhere::INDEX_FILE_SLICE_SIZE_IN_MEGABYTE, 4},
+        };
+    }
+    return milvus::knowhere::Config();
+}
+
+auto
+generate_params() {
+    indexcgo::TypeParams type_params;
+    indexcgo::IndexParams index_params;
+
+    auto configs = generate_conf(milvus::knowhere::IndexEnum::INDEX_FAISS_IVFPQ);
+    for (auto& [key, value] : configs.items()) {
+        auto param = index_params.add_params();
+        auto value_str = value.is_string() ? value.get<std::string>() : value.dump();
+        param->set_key(key);
+        param->set_value(value_str);
+    }
+
+    return std::make_tuple(type_params, index_params);
+}
+}  // namespace
+
+TEST(IndexWrapperTest, Constructor) {
+    auto [type_params, index_params] = generate_params();
+    std::string type_params_str, index_params_str;
+    bool ok;
+
+    ok = type_params.SerializeToString(&type_params_str);
+    assert(ok);
+    ok = index_params.SerializeToString(&index_params_str);
+    assert(ok);
+
+    auto index =
+        std::make_unique<milvus::indexbuilder::IndexWrapper>(type_params_str.c_str(), index_params_str.c_str());
+}
+
+TEST(IndexWrapperTest, Dim) {
+    auto [type_params, index_params] = generate_params();
+    std::string type_params_str, index_params_str;
+    bool ok;
+
+    ok = type_params.SerializeToString(&type_params_str);
+    assert(ok);
+    ok = index_params.SerializeToString(&index_params_str);
+    assert(ok);
+
+    auto index =
+        std::make_unique<milvus::indexbuilder::IndexWrapper>(type_params_str.c_str(), index_params_str.c_str());
+    
+    ASSERT_EQ(index->dim(), DIM);
+}
+
+TEST(IndexWrapperTest, BuildWithoutIds) {
+    auto [type_params, index_params] = generate_params();
+    std::string type_params_str, index_params_str;
+    bool ok;
+
+    ok = type_params.SerializeToString(&type_params_str);
+    assert(ok);
+    ok = index_params.SerializeToString(&index_params_str);
+    assert(ok);
+
+    auto index =
+        std::make_unique<milvus::indexbuilder::IndexWrapper>(type_params_str.c_str(), index_params_str.c_str());
+
+    auto schema = std::make_shared<milvus::Schema>();
+    schema->AddField("fakevec", milvus::engine::DataType::VECTOR_FLOAT, DIM, faiss::MetricType::METRIC_L2);
+    auto dataset = milvus::segcore::DataGen(schema, NB);
+    auto xb_data = dataset.get_col<float>(0);
+
+    index->BuildWithoutIds(milvus::knowhere::GenDataset(NB, DIM, xb_data.data()));
+}
+
+TEST(IndexWrapperTest, Load) {
+    auto type = milvus::knowhere::IndexEnum::INDEX_FAISS_IVFPQ;
+    auto index = milvus::knowhere::VecIndexFactory::GetInstance().CreateVecIndex(type);
+    auto conf = generate_conf(type);
+    auto schema = std::make_shared<milvus::Schema>();
+    schema->AddField("fakevec", milvus::engine::DataType::VECTOR_FLOAT, DIM, faiss::MetricType::METRIC_L2);
+    auto dataset = milvus::segcore::DataGen(schema, NB);
+    auto xb_data = dataset.get_col<float>(0);
+    auto ds = milvus::knowhere::GenDataset(NB, DIM, xb_data.data());
+    index->Train(ds, conf);
+    index->AddWithoutIds(ds, conf);
+    // std::vector<int64_t> ids(NB);
+    // std::iota(ids.begin(), ids.end(), 0); // range(0, NB)
+    // auto ds = milvus::knowhere::GenDatasetWithIds(NB, DIM, xb_data.data(), ids.data());
+    // index->Train(ds, conf);
+    // index->Add(ds, conf);
+    auto binary_set = index->Serialize(conf);
+    auto copy_index = milvus::knowhere::VecIndexFactory::GetInstance().CreateVecIndex(type);
+    copy_index->Load(binary_set);
+}
+
+TEST(IndexWrapperTest, Codec) {
+    auto [type_params, index_params] = generate_params();
+    std::string type_params_str, index_params_str;
+    bool ok;
+
+    ok = type_params.SerializeToString(&type_params_str);
+    assert(ok);
+    ok = index_params.SerializeToString(&index_params_str);
+    assert(ok);
+
+    auto index =
+        std::make_unique<milvus::indexbuilder::IndexWrapper>(type_params_str.c_str(), index_params_str.c_str());
+
+    auto schema = std::make_shared<milvus::Schema>();
+    schema->AddField("fakevec", milvus::engine::DataType::VECTOR_FLOAT, DIM, faiss::MetricType::METRIC_L2);
+    auto dataset = milvus::segcore::DataGen(schema, NB);
+    auto xb_data = dataset.get_col<float>(0);
+
+    index->BuildWithoutIds(milvus::knowhere::GenDataset(NB, DIM, xb_data.data()));
+
+    auto binary = index->Serialize();
+    auto copy_index =
+        std::make_unique<milvus::indexbuilder::IndexWrapper>(type_params_str.c_str(), index_params_str.c_str());
+    copy_index->Load(binary.data, binary.size);
+    ASSERT_EQ(copy_index->dim(), copy_index->dim());
+    auto copy_binary = copy_index->Serialize();
+    ASSERT_EQ(binary.size, copy_binary.size);
+    ASSERT_EQ(strcmp(binary.data, copy_binary.data), 0);
+}
diff --git a/internal/indexbuilder/index.go b/internal/indexbuilder/index.go
index 278677ec45ccd9027d3bd69e03d4da830357ff1b..fadaa2b356a03c3a626e47cc15c0318068c86160 100644
--- a/internal/indexbuilder/index.go
+++ b/internal/indexbuilder/index.go
@@ -18,14 +18,11 @@ import (
 	"github.com/golang/protobuf/proto"
 	"github.com/zilliztech/milvus-distributed/internal/proto/commonpb"
 	"github.com/zilliztech/milvus-distributed/internal/proto/indexcgopb"
+	"github.com/zilliztech/milvus-distributed/internal/storage"
 )
 
 // TODO: use storage.Blob instead later
-// type Blob = storage.Blob
-type Blob struct {
-	Key   string
-	Value []byte
-}
+type Blob = storage.Blob
 
 type Index interface {
 	Serialize() ([]*Blob, error)
@@ -75,9 +72,9 @@ func (index *CIndex) Load(blobs []*Blob) error {
 
 	/*
 		void
-		LoadFromSlicedBuffer(CIndex index, const char* serialized_sliced_blob_buffer);
+		LoadFromSlicedBuffer(CIndex index, const char* serialized_sliced_blob_buffer, int32_t size);
 	*/
-	C.LoadFromSlicedBuffer(index.indexPtr, (*C.char)(unsafe.Pointer(&datas[0])))
+	C.LoadFromSlicedBuffer(index.indexPtr, (*C.char)(unsafe.Pointer(&datas[0])), (C.int32_t)(len(datas)))
 	return nil
 }
 
diff --git a/internal/indexbuilder/task.go b/internal/indexbuilder/task.go
index 5819e565db90573ab5bd59f3191f54f32a503704..f4e73aa27552978936419d2317fd54ba2815308a 100644
--- a/internal/indexbuilder/task.go
+++ b/internal/indexbuilder/task.go
@@ -198,13 +198,7 @@ func (it *IndexBuildTask) Execute() error {
 		}, nil
 	}
 	getStorageBlobs := func(blobs []*Blob) []*storage.Blob {
-		// when storage.Blob.Key & storage.Blob.Value is visible,
-		// use `return blobs`
-		ret := make([]*storage.Blob, 0)
-		for _, blob := range blobs {
-			ret = append(ret, storage.NewBlob(blob.Key, blob.Value))
-		}
-		return ret
+		return blobs
 	}
 
 	toLoadDataPaths := it.indexMeta.Req.GetDataPaths()
@@ -259,7 +253,7 @@ func (it *IndexBuildTask) Execute() error {
 
 		it.savePaths = make([]string, 0)
 		for _, blob := range serializedIndexBlobs {
-			key, value := blob.GetKey(), blob.GetValue()
+			key, value := blob.Key, blob.Value
 			savePath := getSavePathByKey(key)
 			err := saveBlob(savePath, value)
 			if err != nil {