7.1 DFS Overview
 What is the Distributed File System?
 How DFS Namespaces and DFS Replication Work
 DFS Scenarios
 Types of DFS Namespaces
 What are Folders and Folder Targets?
 Namespace Server Requirements
What is the Distributed File System?
The Distributed File System incorporates technologies that provide fault-tolerant
access to geographically dispersed files
DFS technologies include:
• DFS Namespaces - provide a virtual view of shared folders
located on different servers
• DFS Replication - provides high-availability and
fault-tolerance to files and folders
• Remote Differential Compression - provides a compression
technology that is optimized for data transfers over
limited-bandwidth networks
How DFS Namespaces and DFS
Replication Work
User in New York
Server in New York
2
1
\\Contoso.com\Marketing
1
\\NYC-SRV-01\ProjectDocs
Folder
Targets
DFS
Replication
\\LON-SRV-01\ProjectDocs
Namespace
2
User in London
Server in London
1
User types: \\contoso.com\marketing
Client computers contact a namespace server and receive a referral
2
Client computers cache the referral and then contact the first server in the referral
DFS Scenarios
Scenario
Sharing files
across branch
offices
Example
Hub
Hub site
site
Branch
Branch office
office
Hub
Hub site
site
Branch
Branch office
office
Data collection
Hub
Hub site
site
Site
Site 11
Data distribution
Site
Site 22
Types of DFS Namespaces
Characteristics
Domain-based
Stand-alone
Path
\\Domainname\Namespace
\\Servername\Namespace
Location
Active Directory & memory
cache
Server registry & memory
cache
Size
• up to 5000 folders with targets
in Windows 2000 Server mode
• up to 50000 folders with
targets in Windows Server 2008
mode
Up to 50000 folders with
targets
Availability
Namespaces hosted on multiple Server cluster
servers
DFS Replication
Supported
Supported
What are Folders and Folder Targets?
Folder targets include:
Folders:
• Shared folders
(\\server\share)
• Are the primary elements of
a namespace
• Folders in a shared folder
(\\server\share\folder)
• Have at least one folder target
Namespace
Server
• A path to another namespace
(\\domainname\rootname)
Namespace
Folder Targets
\\LDN-SRV-01\Tools
London
Namespace
Root
Folder
Folders with
Targets
\\Contoso\Public
\\NYC-SRV-01\Tools
New York
Software
Tools
Training Guides
\\NYC-SRV-02\Training
New York
Namespace Server Requirements
A namespace server is:
 A domain controller or member server
 Windows Server 2003 or Windows Server 2008
Namespace server considerations:
 Must contain an NTFS volume to host the namespace
 Must be in the same domain if the namespace is
domain-based
 Cannot be a clustered resources if the namespace is
domain-based
7.2 Configuring DFS Namespaces
 Deploying Namespaces for Publishing Content
 Security Requirements for Creating and Managing a
Namespace
 Increasing Availability of a Namespace
 Options for Optimizing a Namespace
Deploying Namespaces for Publishing
Content
To configure a namespace for publishing content:
1.
Create a namespace
2. Create a folder in the namespace
3. Add folder targets
4. Set the ordering method for targets in referrals
Optional tasks:
1.
Set target priority to override referral ordering
2. Enable client failback
3. Replicate folder targets using DFS-R
You may also need to delegate the ability to create & manage namespace
Security Requirements for Creating and
Managing a Namespace
Task
Group
Create a domain-based namespace
Domain Admins
Add a namespace server to a domainbased namespace
Domain Admins
Manage a domain-based namespace
Local Administrators on each
namespace server
Create a stand-alone namespace
Local Administrators group on the
namespace server
Manage a stand-alone namespace
Local Administrators group on the
namespace server
Implement DFS replication
Domain Admins
Increasing Availability of a Namespace
Domain-based namespace:
 Specify additional namespace servers
Stand-alone namespace:
 Create a stand-alone namespace as a cluster resource
Folders:
 Specify additional folder targets
 Replicate folders using DFS Replication
Options for Optimizing a Namespace
Methods for optimizing a namespace include:
 Rename or move a folder
 Disable referrals to a folder
 Referral cache duration
 Namespace polling
7.3 Configuring DFS Replication
 What is DFS Replication?
 What are Replication Groups and Replicated Folders?
 DFS Replication Requirements
 Scalability Considerations for DFS Replication
 Process for Deploying a Multipurpose Replication
Group
 Understanding the Initial Replication Process
 Generating Diagnostic Reports and Propagation Tests
What is DFS Replication (DFS-R)?
DFS-R – multimaster replication engine that supports replication
scheduling & bandwidth throttling
 Uses remote differential compression to efficiently update files





over a limited-bandwidth network
Detects changes on the volume by monitoring the update
sequence number (USN) journal
Uses a staging folder to stage a file before sending & receiving it
Uses a version vector exchange protocol to determine what files
need to be synchronized
Uses a conflict resolution heuristic of “last writer wins” for files
that are in conflict & “earliest creator wins” for name conflicts
Is self-healing & can automatically recover from failure
What are Replication Groups and
Replicated Folders?
• Replication Group
• A set of servers, known as members, that participate in replicating
one or more replicated folders
• Can be configured for multipurpose or data collection purposes
• Replicated Folder
• A folder that is kept synchronized on each member
Replication Group
Connection
Projects\Spec.doc
Member
Proposals\Budget.xls
Projects
Projects
Proposals
Proposals
Replicated
Folders
DFS Replication Requirements
 The Active Directory schema must include the DFS





replication objects
Servers must be Windows Server 2003 R2 or Windows
Server 2008, & must have the DFS replication service
installed
Servers in a replication group must be in the same forest
Replicated folders must be stored on NTFS volumes
On server clusters, replicated folders must be located in
the node’s local storage
Antivirus software must be compatible with DFS
Replication
Scalability Considerations for DFS
Replication
 Each server can be a member of up to 256 replication






groups
Each replication group can contain up to 256 replicated
folders
Each server can have up to 256 connections
The number of replication groups multiplied by the
number of replicated folders multiplied by the number of
simultaneously active connections must be kept to 1024 or
fewer
A replication group can contain up to 256 members
A volume can contain up to 8 million replicated files, & a
server can contain up to 2 TB of replicates files
The max tested file size is 64 GB
Process for Deploying a Multipurpose
Replication Group
1.
2.
3.
4.
5.
6.
7.
Select the type of replication group to create
Specify the name and domain
Add the replication group members
Specify a topology
Specify the replication group schedule and
bandwidth
Specify the primary member
Specify the folders to replicate and the local path on
member servers
Understanding the Initial Replication
Process
1.
2.
3.
4.
5.
Replication of DFS Replication settings
The primary member starts replication
Files are moved to DfsrPrivate\PreExisting
Files are compared and replicated
Primary member designation is removed
Generating Diagnostic Reports and
Propagation Tests
Use the Diagnostic Report
Wizard to:
• Create a health report
• Start a propagation test
• Create a propagation report
End of Chapter 7