When creating a namespace, you must choose one of two namespace types: a stand-alone namespace or a domain-based namespace. In addition, if you choose a domain-based namespace, you must choose a namespace mode: Windows 2000 Server mode or Windows Server 2008 mode.

Choosing a namespace type

Choose a stand-alone namespace if any of the following conditions apply to your environment:

  • Your organization does not use Active Directory Domain Services (AD DS).

  • You want to increase the availability of the namespace by using a failover cluster.

  • You need to create a single namespace with more than 5,000 DFS folders in a domain that does not meet the requirements for a domain-based namespace (Windows Server 2008 mode)—as described later in this topic.

    Note

    To check the size of a namespace, right-click the namespace in the DFS Management console tree, click Properties, and then view the namespace size in the Namespace Properties dialog box. For more information about DFS Namespace scalability, see the Microsoft Web site (https://go.microsoft.com/fwlink/?LinkId=92838).

Choose a domain-based namespace if any of the following conditions apply to your environment:

  • You want to ensure the availability of the namespace by using multiple namespace servers.

  • You want to hide the name of the namespace server from users. This makes it easier to replace the namespace server or migrate the namespace to another server.

Choosing a domain-based namespace mode

If you choose a domain-based namespace, you must choose whether to use the Windows 2000 Server mode or the Windows Server 2008 mode. The Windows Server 2008 mode includes support for access-based enumeration and increased scalability. The domain-based namespace introduced in Windows 2000 Server is now referred to as "domain-based namespace (Windows 2000 Server mode)."

To use the Windows Server 2008 mode, the domain and namespace must meet the following minimum requirements:

  • The forest uses the Windows Server 2003 or higher forest functional level.

  • The domain uses the Windows Server 2008 domain functional level.

  • All namespace servers are running Windows Server 2008.

If your environment supports it, choose the Windows Server 2008 mode when you create new domain-based namespaces. This mode provides additional features and scalability, and also eliminates the possible need to migrate a namespace from the Windows 2000 Server mode.

For information about migrating a namespace to Windows Server 2008 mode, see Migrate a Domain-based Namespace to Windows Server 2008 Mode.

If your environment does not support domain-based namespaces in Windows Server 2008 mode, use the existing Windows 2000 Server mode for the namespace.

Comparing namespace types and modes

The characteristics of each namespace type and mode are described in the following table.

Characteristic Stand-Alone Namespace Domain-based Namespace (Windows 2000 Server Mode) Domain-based Namespace (Windows Server 2008 Mode)

Path to namespace

\\ServerName\RootName

\\NetBIOSDomainName\RootName

\\DNSDomainName\RootName

\\NetBIOSDomainName\RootName

\\DNSDomainName\RootName

Namespace information storage location

In the registry and in a memory cache on the namespace server

In AD DS and in a memory cache on each namespace server

In AD DS and in a memory cache on each namespace server

Namespace size recommendations

The namespace can contain more than 5,000 folders with targets

The size of the namespace object in AD DS should be less than 5 megabytes (MB) to maintain compatibility with domain controllers that are not running Windows Server 2008. This means no more than approximately 5,000 folders with targets.

The namespace can contain more than 5,000 folders with targets

Minimum AD DS forest functional level

AD DS is not required

Windows 2000

Windows Server 2003

Minimum AD DS domain functional level

AD DS is not required

Windows 2000 mixed

Windows Server 2008

Minimum supported namespace servers

Windows 2000 Server

Windows 2000 Server

Windows Server 2008

Support for access-based enumeration (if enabled)

Yes, requires Windows Server 2008 namespace server

No

Yes

Supported methods to ensure namespace availability

Create a stand-alone namespace on a failover cluster.

Use multiple namespace servers to host the namespace. (The namespace servers must be in the same domain.)

Use multiple namespace servers to host the namespace. (The namespace servers must be in the same domain.)

Support for using DFS Replication to replicate folder targets

Supported when joined to an AD DS domain

Supported

Supported


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