Storage Migration Service overview

Applies to: Windows Server 2019, Windows Server 2016, Windows Server 2012 R2, Windows Server (Semi-Annual Channel)

Storage Migration Service makes it easier to migrate servers to a newer version of Windows Server. It provides a graphical tool that inventories data on servers and then transfers the data and configuration to newer servers—all without apps or users having to change anything.

This topic discusses why you'd want to use Storage Migration Service, how the migration process works, and what the requirements are for source and destination servers.

Why use Storage Migration Service

Use Storage Migration Service because you've got a server (or a lot of servers) that you want to migrate to newer hardware or virtual machines. Storage Migration Service is designed to help by doing the following:

  • Inventory multiple servers and their data
  • Rapidly transfer files, file shares, and security configuration from the source servers
  • Optionally take over the identity of the source servers (also known as cutting over) so that users and apps don't have to change anything to access existing data
  • Manage one or multiple migrations from the Windows Admin Center user interface

Diagram showing Storage Migration Service migrating files & configuration from source servers to destination servers, Azure VMs, or Azure File Sync.

Figure 1: Storage Migration Service sources and destinations

How the migration process works

Migration is a three-step process:

  1. Inventory servers to gather info about their files and configuration (shown in Figure 2).
  2. Transfer (copy) data from the source servers to the destination servers.
  3. Cut over to the new servers (optional).
    The destination servers assume the source servers' former identities so that apps and users don't have to change anything.
    The source servers enter a maintenance state where they still contain the same files they always have (we never remove files from the source servers) but are unavailable to users and apps. You can then decommission the servers at your convenience.

Screenshot showing a server ready to be scanned Figure 2: Storage Migration Service inventorying servers


To use Storage Migration Service, you need the following:

  • A source server or failover cluster to migrate files and data from
  • A destination server running Windows Server 2019 (clustered or standalone) to migrate to. Windows Server 2016 and Windows Server 2012 R2 work as well but are around 50% slower
  • An orchestrator server running Windows Server 2019 to manage the migration
    If you're migrating only a few servers and one of the servers is running Windows Server 2019, you can use that as the orchestrator. If you're migrating more servers, we recommend using a separate orchestrator server.
  • A PC or server running Windows Admin Center to run the Storage Migration Service user interface, unless you prefer using PowerShell to manage the migration. The Windows Admin Center and Windows Server 2019 version must both be at least version 1809.

We strongly recommend that the orchestrator and destination computers have at least two cores or two vCPUs, and at least 2 GB of memory. Inventory and transfer operations are significantly faster with more processors and memory.

Security requirements, the Storage Migration Service proxy service, and firewall ports

  • A migration account that is an administrator on the source computers and the orchestrator computer.

  • A migration account that is an administrator on the destination computers and the orchestrator computer.

  • The orchestrator computer must have the File and Printer Sharing (SMB-In) firewall rule enabled inbound.

  • The source and destination computers must have the following firewall rules enabled inbound (though you might already have them enabled):

    • File and Printer Sharing (SMB-In)
    • Netlogon Service (NP-In)
    • Windows Management Instrumentation (DCOM-In)
    • Windows Management Instrumentation (WMI-In)


    Installing the Storage Migration Service Proxy service on a Windows Server 2019 computer automatically opens the necessary firewall ports on that computer. To do so, connect to the destination server in Windows Admin Center and then go to Server Manager (in Windows Admin Center) > Roles and features, select Storage Migration Service Proxy, and then select Install.

  • If the computers belong to an Active Directory Domain Services domain, they should all belong to the same forest. The destination server must also be in the same domain as the source server if you want to transfer the source's domain name to the destination when cutting over. Cutover technically works across domains, but the fully-qualified domain name of the destination will be different from the source...

Requirements for source servers

The source server must run one of the following operating systems:

  • Windows Server, Semi-Annual Channel
  • Windows Server 2019
  • Windows Server 2016
  • Windows Server 2012 R2
  • Windows Server 2012
  • Windows Server 2008 R2
  • Windows Server 2008
  • Windows Server 2003 R2
  • Windows Server 2003
  • Windows Small Business Server 2003 R2
  • Windows Small Business Server 2008
  • Windows Small Business Server 2011
  • Windows Server 2012 Essentials
  • Windows Server 2012 R2 Essentials
  • Windows Server 2016 Essentials
  • Windows Server 2019 Essentials

Note: Windows Small Business Server and Windows Server Essentials are domain controllers. Storage Migration Service can't yet cut over from domain controllers, but can inventory and transfer files from them.

You can migrate the following additional source types if the orchestrator is running Windows Server, version 1903 or later, or if the orchestrator is running an earlier version of Windows Server with KB4512534 installed:

  • Failover clusters
  • Linux servers that use Samba. We've tested the following:
    • CentOS 7
    • Debian GNU/Linux 8
    • RedHat Enterprise Linux 7.6
    • SUSE Linux Enterprise Server (SLES) 11 SP4
    • Ubuntu 16.04 LTS and 12.04.5 LTS
    • Samba 4.8, 4.7, 4.3, 4.2, and 3.6

Requirements for destination servers

The destination server must run one of the following operating systems:

  • Windows Server, Semi-Annual Channel
  • Windows Server 2019
  • Windows Server 2016
  • Windows Server 2012 R2


Destination servers running Windows Server 2019 or Windows Server, Semi-Annual Channel or later have double the transfer performance of earlier versions of Windows Server. This performance boost is due to the inclusion of a built-in Storage Migration Service proxy service, which also opens the necessary firewall ports if they're not already open.

What's new in Storage Migration Service

The following new features are available when running the Storage Migration Server orchestrator on Windows Server, version 1903 or later, or an earlier version of Windows Server with KB4512534 installed:

  • Migrate local users and groups to the new server
  • Migrate storage from failover clusters, migrate to failover clusters, and migrate between standalone servers and failover clusters
  • Migrate storage from a Linux server that uses Samba
  • More easily sync migrated shares into Azure by using Azure File Sync
  • Migrate to new networks such as Azure

See also