diff --git a/cpp/conf/server_config.yaml b/cpp/conf/server_config.yaml
index 0053ba365a..359f8d86bf 100644
--- a/cpp/conf/server_config.yaml
+++ b/cpp/conf/server_config.yaml
@@ -5,7 +5,7 @@ server_config:
   mode: single                # milvus deployment type: single, cluster
 
 db_config:
-  db_path: /opt/milvus             # milvus data storage path
+  db_path: /tmp/milvus             # milvus data storage path
   db_backend_url: http://127.0.0.1 # meta database uri
   index_building_threshold: 1024   # index building trigger threshold, default: 1024, unit: MB
   archive_disk_threshold: 512      # triger archive action if storage size exceed this value, unit: GB
@@ -22,7 +22,10 @@ metric_config:
 
 
 license_config:         # license configure
-  license_path: "/opt/milvus/system.license" # license file path
+  license_path: "/tmp/milvus/system.license" # license file path
 
 cache_config:           # cache configure
   cpu_cache_capacity: 16   # how many memory are used as cache, unit: GB, range: 0 ~ less than total memory
+
+engine_config:
+  nprobe: 3000
\ No newline at end of file
diff --git a/cpp/src/wrapper/Index.cpp b/cpp/src/wrapper/Index.cpp
index c306b65e1a..b051bfb07e 100644
--- a/cpp/src/wrapper/Index.cpp
+++ b/cpp/src/wrapper/Index.cpp
@@ -14,6 +14,8 @@
 #include "Index.h"
 #include "faiss/index_io.h"
 #include "faiss/IndexIVF.h"
+#include <faiss/IVFlib.h>
+#include "server/ServerConfig.h"
 
 namespace zilliz {
 namespace milvus {
@@ -23,6 +25,32 @@ using std::string;
 using std::unordered_map;
 using std::vector;
 
+class Nprobe {
+ public:
+    static Nprobe &GetInstance() {
+        static Nprobe instance;
+        return instance;
+    }
+
+    void SelectNprobe() {
+        using namespace zilliz::milvus::server;
+        ServerConfig &config = ServerConfig::GetInstance();
+        ConfigNode engine_config = config.GetConfig(CONFIG_ENGINE);
+        nprobe_ = engine_config.GetInt32Value(CONFIG_NPROBE, 1000);
+    }
+
+    size_t GetNprobe() {
+        return nprobe_;
+    }
+
+ private:
+    Nprobe() : nprobe_(1000) { SelectNprobe(); }
+
+ private:
+    size_t nprobe_;
+};
+
+
 Index::Index(const std::shared_ptr<faiss::Index> &raw_index) {
     index_ = raw_index;
     dim = index_->d;
@@ -57,7 +85,8 @@ bool Index::add_with_ids(idx_t n, const float *xdata, const long *xids) {
 bool Index::search(idx_t n, const float *data, idx_t k, float *distances, long *labels) const {
     try {
         if(auto ivf_index = std::dynamic_pointer_cast<faiss::IndexIVF>(index_)) {
-            ivf_index->nprobe = 100;
+            ivf_index->nprobe = Nprobe::GetInstance().GetNprobe();
+            std::cout << "nprobe = " << ivf_index->nprobe << std::endl;
         }
         index_->search(n, data, k, distances, labels);
     }
diff --git a/cpp/src/wrapper/Operand.cpp b/cpp/src/wrapper/Operand.cpp
index 30e31067fd..25341676a6 100644
--- a/cpp/src/wrapper/Operand.cpp
+++ b/cpp/src/wrapper/Operand.cpp
@@ -39,7 +39,7 @@ string Operand::get_index_type(const int &nb) {
         }
         case IVF: {
             index_str += (ncent != 0 ? index_type + std::to_string(ncent) :
-                          index_type + std::to_string(int(nb / 1000000.0 * 1638)));
+                          index_type + std::to_string(int(nb / 1000000.0 * 16384)));
             break;
         }
         case IDMAP: {