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Microsoft Azure Storage Data Movement Library (0.9.0)

The Microsoft Azure Storage Data Movement Library designed for high-performance uploading, downloading and copying Azure Storage Blob and File. This library is based on the core data movement framework that powers AzCopy.

For more information about the Azure Storage, please visit Microsoft Azure Storage Documentation.


  • Blobs

    • Download/Upload/Copy Blobs.
    • Synchronous and asynchronous copy Blobs
    • Concurrently transfer Blobs and Blob chunks, define number of concurrent operations
    • Download Specific Blob Snapshot
  • Files

    • Download/Upload/Copy Files.
    • Synchronous and asynchronous copy Files
    • Concurrently transfer Files and File ranges, define number of concurrent operations
  • General

    • Track data transfer progress
    • Recover the data transfer
    • Set Access Condition
    • Set User Agent Suffix
    • Directory/recursive transfer

Getting started

For the best development experience, we recommend that developers use the official Microsoft NuGet packages for libraries. NuGet packages are regularly updated with new functionality and hotfixes.

Target Frameworks

  • .NET Framework 4.5 or above
  • Netstandard2.0


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Download & Install

Via Git

To get the source code of the SDK via git just type:

git clone
cd azure-storage-net-data-movement

Via NuGet

To get the binaries of this library as distributed by Microsoft, ready for use within your project you can also have them installed by the .NET package manager NuGet.

Install-Package Microsoft.Azure.Storage.DataMovement


Azure Storage Client Library

This version depends on Azure Storage Client Library

Code Samples

Find more samples at the sample folder.

Upload a blob

First, include the classes you need, here we include Storage client library, the Storage data movement library and the .NET threading because data movement library provides Task Asynchronous interfaces to transfer storage objects:

using System;
using System.Threading;
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Blob;
using Microsoft.WindowsAzure.Storage.DataMovement;

Now use the interfaces provided by Storage client lib to setup the storage context (find more details at how to use Blob Storage from .NET):

string storageConnectionString = "myStorageConnectionString";
CloudStorageAccount account = CloudStorageAccount.Parse(storageConnectionString);
CloudBlobClient blobClient = account.CreateCloudBlobClient();
CloudBlobContainer blobContainer = blobClient.GetContainerReference("mycontainer");
string sourcePath = "path\\to\\test.txt";
CloudBlockBlob destBlob = blobContainer.GetBlockBlobReference("myblob");

Once you setup the storage blob context, you can start to use WindowsAzure.Storage.DataMovement.TransferManager to upload the blob and track the upload progress,

// Setup the number of the concurrent operations
TransferManager.Configurations.ParallelOperations = 64;
// Setup the transfer context and track the upoload progress
SingleTransferContext context = new SingleTransferContext();
context.ProgressHandler = new Progress<TransferStatus>((progress) =>
	Console.WriteLine("Bytes uploaded: {0}", progress.BytesTransferred);
// Upload a local blob
var task = TransferManager.UploadAsync(
	sourcePath, destBlob, null, context, CancellationToken.None);

Best Practice

Increase .NET HTTP connections limit

By default, the .Net HTTP connection limit is 2. This implies that only two concurrent connections can be maintained. It prevents more parallel connections accessing Azure blob storage from your application.

AzCopy will set ServicePointManager.DefaultConnectionLimit to the number of eight multiple the core number by default. To have a comparable performance when using Data Movement Library alone, we recommend you set this value as well.

ServicePointManager.DefaultConnectionLimit = Environment.ProcessorCount * 8;

Turn off 100-continue

When the property "Expect100Continue" is set to true, client requests that use the PUT and POST methods will add an Expect: 100-continue header to the request and it will expect to receive a 100-Continue response from the server to indicate that the client should send the data to be posted. This mechanism allows clients to avoid sending large amounts of data over the network when the server, based on the request headers, intends to reject the request.

However, once the entire payload is received on the server end, other errors may still occur. And if Windows Azure clients have tested the client well enough to ensure that it is not sending any bad requests, clients could turn off 100-continue so that the entire request is sent in one roundtrip. This is especially true when clients send small size storage objects.

ServicePointManager.Expect100Continue = false;

Pattern/Recursive in DMLib

The following matrix explains how the DirectoryOptions.Recursive and DirectoryOptions.SearchPattern properties work in DMLib.

Source Search Pattern Recursive Search Pattern Example Comments
Local Wildcard Match TRUE "foo*.png" The search pattern is a standard wild card match that is applied to the current directory and all subdirectories.
Local Wildcard Match FALSE "foo*.png" The search pattern is a standard wild card match that is applied to the current directory only.
Azure Blob Prefix Match TRUE <domainname>/<container>/<virtualdirectory>/<blobprefix>

The search pattern is a prefix match.
Azure Blob Exact Match FALSE <domainname>/<container>/<virtualdirectory>/<fullblobname>

The search pattern is an exact match. If the search pattern is an empty string, no blobs will be matched.
Azure File N/A TRUE N/A Recursive search is not supported and will return an error.
Azure File Exact Match FALSE <domainname>/<share>/<directory>/<fullfilename>

The search pattern is an exact match. If the search pattern is an empty string, no files will be matched.
  • Default pattern option:

    • Local:*
    • Blob: Empty string
    • File: Empty string
  • Default recursive option: false

Need Help?

Be sure to check out the Microsoft Azure Developer Forums on MSDN if you have trouble with the provided code or use StackOverflow.

Collaborate & Contribute

We gladly accept community contributions.

  • Issues: Please report bugs using the Issues section of GitHub
  • Forums: Interact with the development teams on StackOverflow or the Microsoft Azure Forums
  • Source Code Contributions: Please follow the contribution guidelines for Microsoft Azure open source that details information on onboarding as a contributor

For general suggestions about Microsoft Azure please use our UserVoice forum.

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