Distributed File System

Features and Benefits

The features of Dfs and their benefits for administrators and users are presented in Table 17.1.

Table 17.1 Dfs Features and Benefits

Feature	Description	Benefit
Unified namespace	Linking together network storage resources creates a single, hierarchical structure that behaves as a single, high-capacity hard disk.	Provides a unified view of shared folders that you can customize for individual users and groups. A single drive mapping can reflect hundreds of shared folders.
Name transparency	Users can navigate the logical namespace without having to know the physical locations of the data. The actual data can be moved to any server and the logical Dfs namespace can be reconfigured without affecting the user's view of the namespace.	Provides increased administrative flexibility. You can move shared folders between servers or disk drives without affecting the users' access to the data.
Flexible storage management	Individual shared folders that are part of the Dfs root can be taken offline without affecting the remaining portion of the namespace. You can remove and replace an entire server by adding the path of a new server to the namespace.	Allows management of physical network storage independent of its logical representation to users. The Dfs namespace can be extended at any time to incorporate additional disk storage.
Graphical administration	Each root in the Dfs topology is administered with an easy-to-use graphical interface in Microsoft Management Console (MMC). This permits configuration of shared folders and Dfs links and the administration of remote Dfs roots.	Reduces training time and the need for full-time server administrators.
Load sharing	Roots and replicas hosted on two or more computers provide load sharing. As users request files from the node in the Dfs namespace, they randomly select one of the computers for the accessed node.	Randomly distributes file access across multiple disk drives or servers to balance loads and improve response time during peak usage periods.
Availability	Roots and replicas hosted on two or more computers can be specified as a replica set under the same logical Dfs name to provide alternate locations for accessing data. If one copy becomes unavailable, another is selected automatically. Copy replication can be manual or automatic.	Keeps important data accessible at all times, even when a server or disk drive fails or when a shared folder or file becomes corrupted. Dfs roots also can be replicated to eliminate them as single points of failure.
Security integration	No additional overhead is necessary for implementing security. A user who connects to a Dfs root is permitted access only to files for which he or she has appropriate permissions. Using the optional FRS replication, identical permissions can be set on physically separate replicas.	Uses standard Windows 2000 file and directory permissions for easy administration and secure access.
Intelligent client caching	Information about the Dfs namespace for a shared folder is not cached on a client until a user actually requests access to the folder. The next time the client requires access to the same portion of the Dfs namespace, the client uses the cached referral rather than obtaining a new referral.	Using a local cache on the client minimizes network traffic and improves user response times.
Dfs awareness for clients running Microsoft® Windows® 95 and Windows® 98	Because Dfs support has been integrated into the server message block (SMB) redirector, no additional memory is required to run the Dfs clients for Microsoft® Windows NT® version 4.0 and Windows 98. Dfs includes an add-on component that permits Windows 95 users to navigate the Dfs namespace. However, clients that are running Windows 98 and Windows 95 can gain access to non-SMB volumes only through a server-based gateway such as Gateway Service for NetWare.	Requires no additional resources on client systems for Dfs functions. Extends Dfs benefits to Windows 98 and Windows 95 users.
Interoperability with other network operating systems	Any shared folder that is accessible through a redirector on Windows 2000 can participate in the Dfs namespace. This can be through client redirectors or through server-based gateway technology.	Supports heterogeneous network operating systems such as MS-DOS®, Microsoft® Windows® version 3.x, Windows 95, Windows 98, and Windows NT 4.0 and earlier.