diff --git a/internal/core/src/mmap/Column.h b/internal/core/src/mmap/Column.h
index fb7a41bf6f704..2e9e71f31f780 100644
--- a/internal/core/src/mmap/Column.h
+++ b/internal/core/src/mmap/Column.h
@@ -388,11 +388,13 @@ class ColumnBase {
                 mapped_size);
             milvus::monitor::internal_mmap_in_used_space_bytes_anon.Increment(
                 mapped_size);
+            milvus::monitor::internal_mmap_in_used_count_anon.Increment();
         } else if (mapping_type_ == MappingType::MAP_WITH_FILE) {
             milvus::monitor::internal_mmap_allocated_space_bytes_file.Observe(
                 mapped_size);
             milvus::monitor::internal_mmap_in_used_space_bytes_file.Increment(
                 mapped_size);
+            milvus::monitor::internal_mmap_in_used_count_file.Increment();
         }
         // else: does not update metric for MAP_WITH_MANAGER, MmapChunkManagerPtr
         // will update metric itself.
@@ -403,9 +405,11 @@ class ColumnBase {
         if (mapping_type_ == MappingType::MAP_WITH_ANONYMOUS) {
             milvus::monitor::internal_mmap_in_used_space_bytes_anon.Decrement(
                 mapped_size);
+            milvus::monitor::internal_mmap_in_used_count_anon.Decrement();
         } else if (mapping_type_ == MappingType::MAP_WITH_FILE) {
             milvus::monitor::internal_mmap_in_used_space_bytes_file.Decrement(
                 mapped_size);
+            milvus::monitor::internal_mmap_in_used_count_file.Decrement();
         }
         // else: does not update metric for MAP_WITH_MANAGER, MmapChunkManagerPtr
         // will update metric itself.
diff --git a/internal/core/src/monitor/prometheus_client.cpp b/internal/core/src/monitor/prometheus_client.cpp
index 50ca5550559a2..9b5cf5603ed83 100644
--- a/internal/core/src/monitor/prometheus_client.cpp
+++ b/internal/core/src/monitor/prometheus_client.cpp
@@ -196,6 +196,10 @@ std::map<std::string, std::string> mmapAllocatedSpaceAnonLabel = {
     {"type", "anon"}};
 std::map<std::string, std::string> mmapAllocatedSpaceFileLabel = {
     {"type", "file"}};
+std::map<std::string, std::string> mmapAllocatedCountAnonLabel = {
+    {"type", "anon"}};
+std::map<std::string, std::string> mmapAllocatedCountFileLabel = {
+    {"type", "file"}};
 
 DEFINE_PROMETHEUS_HISTOGRAM_FAMILY(internal_mmap_allocated_space_bytes,
                                    "[cpp]mmap allocated space stats")
@@ -218,4 +222,12 @@ DEFINE_PROMETHEUS_GAUGE(internal_mmap_in_used_space_bytes_anon,
 DEFINE_PROMETHEUS_GAUGE(internal_mmap_in_used_space_bytes_file,
                         internal_mmap_in_used_space_bytes,
                         mmapAllocatedSpaceFileLabel)
+DEFINE_PROMETHEUS_GAUGE_FAMILY(internal_mmap_in_used_count,
+                               "[cpp]mmap in used count stats")
+DEFINE_PROMETHEUS_GAUGE(internal_mmap_in_used_count_anon,
+                        internal_mmap_in_used_count,
+                        mmapAllocatedCountAnonLabel)
+DEFINE_PROMETHEUS_GAUGE(internal_mmap_in_used_count_file,
+                        internal_mmap_in_used_count,
+                        mmapAllocatedCountFileLabel)
 }  // namespace milvus::monitor
diff --git a/internal/core/src/monitor/prometheus_client.h b/internal/core/src/monitor/prometheus_client.h
index 29b625b5e9fc2..23b4f58a87e1b 100644
--- a/internal/core/src/monitor/prometheus_client.h
+++ b/internal/core/src/monitor/prometheus_client.h
@@ -127,6 +127,9 @@ DECLARE_PROMETHEUS_HISTOGRAM(internal_mmap_allocated_space_bytes_file);
 DECLARE_PROMETHEUS_GAUGE_FAMILY(internal_mmap_in_used_space_bytes);
 DECLARE_PROMETHEUS_GAUGE(internal_mmap_in_used_space_bytes_anon);
 DECLARE_PROMETHEUS_GAUGE(internal_mmap_in_used_space_bytes_file);
+DECLARE_PROMETHEUS_GAUGE_FAMILY(internal_mmap_in_used_count);
+DECLARE_PROMETHEUS_GAUGE(internal_mmap_in_used_count_anon);
+DECLARE_PROMETHEUS_GAUGE(internal_mmap_in_used_count_file);
 
 // search metrics
 DECLARE_PROMETHEUS_HISTOGRAM_FAMILY(internal_core_search_latency);
diff --git a/internal/core/src/storage/MmapChunkManager.cpp b/internal/core/src/storage/MmapChunkManager.cpp
index fffd1ea7d09e1..f2acc0adebfc0 100644
--- a/internal/core/src/storage/MmapChunkManager.cpp
+++ b/internal/core/src/storage/MmapChunkManager.cpp
@@ -73,6 +73,7 @@ MmapBlock::Init() {
         file_size_);
     milvus::monitor::internal_mmap_in_used_space_bytes_file.Increment(
         file_size_);
+    milvus::monitor::internal_mmap_in_used_count_file.Increment();
     is_valid_ = true;
     allocated_size_.fetch_add(file_size_);
 }
@@ -98,6 +99,7 @@ MmapBlock::Close() {
     allocated_size_.fetch_sub(file_size_);
     milvus::monitor::internal_mmap_in_used_space_bytes_file.Decrement(
         file_size_);
+    milvus::monitor::internal_mmap_in_used_count_file.Decrement();
     is_valid_ = false;
 }