From 857c76b7de62be6fdf31cba1c8da88e0148919cf Mon Sep 17 00:00:00 2001
From: Jinming Hu <jinmhu@microsoft.com>
Date: Tue, 17 Mar 2026 15:27:05 +1100
Subject: [PATCH 1/4] change default transfer parameters

---
 .../inc/azure/storage/blobs/blob_options.hpp     | 10 +++++++---
 .../src/block_blob_client.cpp                    |  4 ++--
 sdk/storage/azure-storage-common/CMakeLists.txt  |  1 +
 .../common/internal/concurrent_transfer.hpp      |  2 ++
 .../src/concurrent_transfer.cpp                  | 16 ++++++++++++++++
 .../storage/files/datalake/datalake_options.hpp  |  4 +++-
 .../azure/storage/files/shares/share_options.hpp | 10 +++++++---
 7 files changed, 38 insertions(+), 9 deletions(-)
 create mode 100644 sdk/storage/azure-storage-common/src/concurrent_transfer.cpp

diff --git a/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp b/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp
index 7ad7759071..1cbce7edfe 100644
--- a/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp
+++ b/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp
@@ -11,6 +11,7 @@
 #include <azure/core/modified_conditions.hpp>
 #include <azure/storage/common/access_conditions.hpp>
 #include <azure/storage/common/crypt.hpp>
+#include <azure/storage/common/internal/concurrent_transfer.hpp>
 
 #include <chrono>
 #include <cstdint>
@@ -771,12 +772,14 @@ namespace Azure { namespace Storage { namespace Blobs {
       /**
        * @brief The maximum number of bytes in a single request.
        */
-      int64_t ChunkSize = 4 * 1024 * 1024;
+      int64_t ChunkSize = 16 * 1024 * 1024;
 
       /**
        * @brief The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency = 5;
+      int32_t Concurrency = _internal::GetHardwareConcurrency() / 2 != 0
+          ? _internal::GetHardwareConcurrency() / 2
+          : 1;
     } TransferOptions;
 
     /**
@@ -1023,7 +1026,8 @@ namespace Azure { namespace Storage { namespace Blobs {
       /**
        * @brief The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency = 5;
+      int32_t Concurrency
+          = _internal::GetHardwareConcurrency() != 0 ? _internal::GetHardwareConcurrency() : 1;
     } TransferOptions;
 
     /**
diff --git a/sdk/storage/azure-storage-blobs/src/block_blob_client.cpp b/sdk/storage/azure-storage-blobs/src/block_blob_client.cpp
index 7401e5203f..2628c9f3b9 100644
--- a/sdk/storage/azure-storage-blobs/src/block_blob_client.cpp
+++ b/sdk/storage/azure-storage-blobs/src/block_blob_client.cpp
@@ -178,7 +178,7 @@ namespace Azure { namespace Storage { namespace Blobs {
       const UploadBlockBlobFromOptions& options,
       const Azure::Core::Context& context) const
   {
-    constexpr int64_t DefaultStageBlockSize = 4 * 1024 * 1024ULL;
+    constexpr int64_t DefaultStageBlockSize = 16 * 1024 * 1024ULL;
     constexpr int64_t MaxStageBlockSize = 4000 * 1024 * 1024ULL;
     constexpr int64_t MaxBlockNumber = 50000;
     constexpr int64_t BlockGrainSize = 1 * 1024 * 1024;
@@ -270,7 +270,7 @@ namespace Azure { namespace Storage { namespace Blobs {
       const UploadBlockBlobFromOptions& options,
       const Azure::Core::Context& context) const
   {
-    constexpr int64_t DefaultStageBlockSize = 4 * 1024 * 1024ULL;
+    constexpr int64_t DefaultStageBlockSize = 16 * 1024 * 1024ULL;
     constexpr int64_t MaxStageBlockSize = 4000 * 1024 * 1024ULL;
     constexpr int64_t MaxBlockNumber = 50000;
     constexpr int64_t BlockGrainSize = 1 * 1024 * 1024;
diff --git a/sdk/storage/azure-storage-common/CMakeLists.txt b/sdk/storage/azure-storage-common/CMakeLists.txt
index a91e1baaf7..f31c1ce44d 100644
--- a/sdk/storage/azure-storage-common/CMakeLists.txt
+++ b/sdk/storage/azure-storage-common/CMakeLists.txt
@@ -70,6 +70,7 @@ set(
 set(
   AZURE_STORAGE_COMMON_SOURCE
     src/account_sas_builder.cpp
+    src/concurrent_transfer.cpp
     src/crypt.cpp
     src/file_io.cpp
     src/private/package_version.hpp
diff --git a/sdk/storage/azure-storage-common/inc/azure/storage/common/internal/concurrent_transfer.hpp b/sdk/storage/azure-storage-common/inc/azure/storage/common/internal/concurrent_transfer.hpp
index 9897c518ae..55f0ed6297 100644
--- a/sdk/storage/azure-storage-common/inc/azure/storage/common/internal/concurrent_transfer.hpp
+++ b/sdk/storage/azure-storage-common/inc/azure/storage/common/internal/concurrent_transfer.hpp
@@ -13,6 +13,8 @@
 
 namespace Azure { namespace Storage { namespace _internal {
 
+  int GetHardwareConcurrency();
+
   inline void ConcurrentTransfer(
       int64_t offset,
       int64_t length,
diff --git a/sdk/storage/azure-storage-common/src/concurrent_transfer.cpp b/sdk/storage/azure-storage-common/src/concurrent_transfer.cpp
new file mode 100644
index 0000000000..d130eb69d8
--- /dev/null
+++ b/sdk/storage/azure-storage-common/src/concurrent_transfer.cpp
@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+#include "azure/storage/common/internal/concurrent_transfer.hpp"
+
+#include <thread>
+
+namespace Azure { namespace Storage { namespace _internal {
+
+  int GetHardwareConcurrency()
+  {
+    static int c = std::thread::hardware_concurrency();
+    return c;
+  }
+
+}}} // namespace Azure::Storage::_internal
\ No newline at end of file
diff --git a/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp b/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp
index 26220a39ae..38eb156f03 100644
--- a/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp
+++ b/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp
@@ -9,6 +9,7 @@
 #include <azure/core/nullable.hpp>
 #include <azure/storage/blobs/blob_options.hpp>
 #include <azure/storage/common/access_conditions.hpp>
+#include <azure/storage/common/internal/concurrent_transfer.hpp>
 
 #include <cstdint>
 #include <memory>
@@ -1017,7 +1018,8 @@ namespace Azure { namespace Storage { namespace Files { namespace DataLake {
       /**
        * The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency = 5;
+      int32_t Concurrency
+          = _internal::GetHardwareConcurrency() != 0 ? _internal::GetHardwareConcurrency() : 1;
     } TransferOptions;
 
     /**
diff --git a/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp b/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
index a4f808c31c..5d675303d1 100644
--- a/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
+++ b/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
@@ -9,6 +9,7 @@
 #include <azure/core/internal/extendable_enumeration.hpp>
 #include <azure/core/nullable.hpp>
 #include <azure/storage/common/access_conditions.hpp>
+#include <azure/storage/common/internal/concurrent_transfer.hpp>
 
 #include <memory>
 #include <string>
@@ -1325,12 +1326,14 @@ namespace Azure { namespace Storage { namespace Files { namespace Shares {
       /**
        * The maximum number of bytes in a single request.
        */
-      int64_t ChunkSize = 4 * 1024 * 1024;
+      int64_t ChunkSize = 16 * 1024 * 1024;
 
       /**
        * The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency = 5;
+      int32_t Concurrency = _internal::GetHardwareConcurrency() / 2 != 0
+          ? _internal::GetHardwareConcurrency() / 2
+          : 1;
     } TransferOptions;
   };
 
@@ -1399,7 +1402,8 @@ namespace Azure { namespace Storage { namespace Files { namespace Shares {
       /**
        * The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency = 5;
+      int32_t Concurrency
+          = _internal::GetHardwareConcurrency() != 0 ? _internal::GetHardwareConcurrency() : 1;
     } TransferOptions;
   };
 

From 47d82a6e3638e6013d863e46938e75cb34cc04bd Mon Sep 17 00:00:00 2001
From: Jinming Hu <jinmhu@microsoft.com>
Date: Wed, 20 May 2026 10:38:18 +1000
Subject: [PATCH 2/4] Revert some changes

---
 .../inc/azure/storage/blobs/blob_options.hpp             | 9 +++------
 .../azure-storage-blobs/src/block_blob_client.cpp        | 4 ++--
 .../azure/storage/files/datalake/datalake_options.hpp    | 3 +--
 .../inc/azure/storage/files/shares/share_options.hpp     | 6 ++----
 4 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp b/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp
index 1cbce7edfe..12439e7ea6 100644
--- a/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp
+++ b/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp
@@ -772,14 +772,12 @@ namespace Azure { namespace Storage { namespace Blobs {
       /**
        * @brief The maximum number of bytes in a single request.
        */
-      int64_t ChunkSize = 16 * 1024 * 1024;
+      int64_t ChunkSize = 4 * 1024 * 1024;
 
       /**
        * @brief The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency = _internal::GetHardwareConcurrency() / 2 != 0
-          ? _internal::GetHardwareConcurrency() / 2
-          : 1;
+      int32_t Concurrency = std::min(96, std::max(8, _internal::GetHardwareConcurrency()));
     } TransferOptions;
 
     /**
@@ -1026,8 +1024,7 @@ namespace Azure { namespace Storage { namespace Blobs {
       /**
        * @brief The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency
-          = _internal::GetHardwareConcurrency() != 0 ? _internal::GetHardwareConcurrency() : 1;
+      int32_t Concurrency = std::min(96, std::max(8, _internal::GetHardwareConcurrency()));
     } TransferOptions;
 
     /**
diff --git a/sdk/storage/azure-storage-blobs/src/block_blob_client.cpp b/sdk/storage/azure-storage-blobs/src/block_blob_client.cpp
index 2628c9f3b9..7401e5203f 100644
--- a/sdk/storage/azure-storage-blobs/src/block_blob_client.cpp
+++ b/sdk/storage/azure-storage-blobs/src/block_blob_client.cpp
@@ -178,7 +178,7 @@ namespace Azure { namespace Storage { namespace Blobs {
       const UploadBlockBlobFromOptions& options,
       const Azure::Core::Context& context) const
   {
-    constexpr int64_t DefaultStageBlockSize = 16 * 1024 * 1024ULL;
+    constexpr int64_t DefaultStageBlockSize = 4 * 1024 * 1024ULL;
     constexpr int64_t MaxStageBlockSize = 4000 * 1024 * 1024ULL;
     constexpr int64_t MaxBlockNumber = 50000;
     constexpr int64_t BlockGrainSize = 1 * 1024 * 1024;
@@ -270,7 +270,7 @@ namespace Azure { namespace Storage { namespace Blobs {
       const UploadBlockBlobFromOptions& options,
       const Azure::Core::Context& context) const
   {
-    constexpr int64_t DefaultStageBlockSize = 16 * 1024 * 1024ULL;
+    constexpr int64_t DefaultStageBlockSize = 4 * 1024 * 1024ULL;
     constexpr int64_t MaxStageBlockSize = 4000 * 1024 * 1024ULL;
     constexpr int64_t MaxBlockNumber = 50000;
     constexpr int64_t BlockGrainSize = 1 * 1024 * 1024;
diff --git a/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp b/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp
index 38eb156f03..8d9b8bcb7e 100644
--- a/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp
+++ b/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp
@@ -1018,8 +1018,7 @@ namespace Azure { namespace Storage { namespace Files { namespace DataLake {
       /**
        * The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency
-          = _internal::GetHardwareConcurrency() != 0 ? _internal::GetHardwareConcurrency() : 1;
+      int32_t Concurrency = std::min(96, std::max(8, _internal::GetHardwareConcurrency()));
     } TransferOptions;
 
     /**
diff --git a/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp b/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
index 5d675303d1..cef07d1c2b 100644
--- a/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
+++ b/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
@@ -1326,14 +1326,12 @@ namespace Azure { namespace Storage { namespace Files { namespace Shares {
       /**
        * The maximum number of bytes in a single request.
        */
-      int64_t ChunkSize = 16 * 1024 * 1024;
+      int64_t ChunkSize = 4 * 1024 * 1024;
 
       /**
        * The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency = _internal::GetHardwareConcurrency() / 2 != 0
-          ? _internal::GetHardwareConcurrency() / 2
-          : 1;
+      int32_t Concurrency = std::min(96, std::max(8, _internal::GetHardwareConcurrency()));
     } TransferOptions;
   };
 

From c6c5d369ea8593e81371f2e84aedfc486785b511 Mon Sep 17 00:00:00 2001
From: Jinming Hu <jinmhu@microsoft.com>
Date: Wed, 20 May 2026 10:41:30 +1000
Subject: [PATCH 3/4] fix

---
 .../inc/azure/storage/blobs/blob_options.hpp                 | 5 +++--
 .../inc/azure/storage/files/datalake/datalake_options.hpp    | 3 ++-
 .../inc/azure/storage/files/shares/share_options.hpp         | 3 ++-
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp b/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp
index 12439e7ea6..e883f84c86 100644
--- a/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp
+++ b/sdk/storage/azure-storage-blobs/inc/azure/storage/blobs/blob_options.hpp
@@ -13,6 +13,7 @@
 #include <azure/storage/common/crypt.hpp>
 #include <azure/storage/common/internal/concurrent_transfer.hpp>
 
+#include <algorithm>
 #include <chrono>
 #include <cstdint>
 #include <memory>
@@ -777,7 +778,7 @@ namespace Azure { namespace Storage { namespace Blobs {
       /**
        * @brief The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency = std::min(96, std::max(8, _internal::GetHardwareConcurrency()));
+      int32_t Concurrency = (std::min)(96, (std::max)(8, _internal::GetHardwareConcurrency()));
     } TransferOptions;
 
     /**
@@ -1024,7 +1025,7 @@ namespace Azure { namespace Storage { namespace Blobs {
       /**
        * @brief The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency = std::min(96, std::max(8, _internal::GetHardwareConcurrency()));
+      int32_t Concurrency = (std::min)(96, (std::max)(8, _internal::GetHardwareConcurrency()));
     } TransferOptions;
 
     /**
diff --git a/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp b/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp
index 8d9b8bcb7e..5c26ce81ec 100644
--- a/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp
+++ b/sdk/storage/azure-storage-files-datalake/inc/azure/storage/files/datalake/datalake_options.hpp
@@ -11,6 +11,7 @@
 #include <azure/storage/common/access_conditions.hpp>
 #include <azure/storage/common/internal/concurrent_transfer.hpp>
 
+#include <algorithm>
 #include <cstdint>
 #include <memory>
 #include <string>
@@ -1018,7 +1019,7 @@ namespace Azure { namespace Storage { namespace Files { namespace DataLake {
       /**
        * The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency = std::min(96, std::max(8, _internal::GetHardwareConcurrency()));
+      int32_t Concurrency = (std::min)(96, (std::max)(8, _internal::GetHardwareConcurrency()));
     } TransferOptions;
 
     /**
diff --git a/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp b/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
index cef07d1c2b..623d93c7e5 100644
--- a/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
+++ b/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
@@ -11,6 +11,7 @@
 #include <azure/storage/common/access_conditions.hpp>
 #include <azure/storage/common/internal/concurrent_transfer.hpp>
 
+#include <algorithm>
 #include <memory>
 #include <string>
 #include <vector>
@@ -1331,7 +1332,7 @@ namespace Azure { namespace Storage { namespace Files { namespace Shares {
       /**
        * The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency = std::min(96, std::max(8, _internal::GetHardwareConcurrency()));
+      int32_t Concurrency = (std::min)(96, (std::max)(8, _internal::GetHardwareConcurrency()));
     } TransferOptions;
   };
 

From 8e7ab3eb79277a63c875e8ac7374e71e809ee297 Mon Sep 17 00:00:00 2001
From: Jinming Hu <jinmhu@microsoft.com>
Date: Wed, 20 May 2026 10:44:35 +1000
Subject: [PATCH 4/4] fix

---
 sdk/storage/azure-storage-common/src/concurrent_transfer.cpp  | 4 ++--
 .../inc/azure/storage/files/shares/share_options.hpp          | 3 +--
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/sdk/storage/azure-storage-common/src/concurrent_transfer.cpp b/sdk/storage/azure-storage-common/src/concurrent_transfer.cpp
index d130eb69d8..14b3d77a71 100644
--- a/sdk/storage/azure-storage-common/src/concurrent_transfer.cpp
+++ b/sdk/storage/azure-storage-common/src/concurrent_transfer.cpp
@@ -9,8 +9,8 @@ namespace Azure { namespace Storage { namespace _internal {
 
   int GetHardwareConcurrency()
   {
-    static int c = std::thread::hardware_concurrency();
+    static int c = static_cast<int>(std::thread::hardware_concurrency());
     return c;
   }
 
-}}} // namespace Azure::Storage::_internal
\ No newline at end of file
+}}} // namespace Azure::Storage::_internal
diff --git a/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp b/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
index 623d93c7e5..527641dc28 100644
--- a/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
+++ b/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/share_options.hpp
@@ -1401,8 +1401,7 @@ namespace Azure { namespace Storage { namespace Files { namespace Shares {
       /**
        * The maximum number of threads that may be used in a parallel transfer.
        */
-      int32_t Concurrency
-          = _internal::GetHardwareConcurrency() != 0 ? _internal::GetHardwareConcurrency() : 1;
+      int32_t Concurrency = (std::min)(96, (std::max)(8, _internal::GetHardwareConcurrency()));
     } TransferOptions;
   };