Jesper M. Christensen

SharePoint and Security

Make your file shares redundant with DFS

The situation

Every company use file-servers for storing business data and these are getting a more important role as the IT infrastructure evolves. Take a minute and think about the following scenario:

An electronic component on a main file-server has a malfunction and the server goes black 6’o’clock in the morning leaving the users without access to the files. The replacement of this component, or the whole server, takes 8 hours to be fixed and get the server up running as before.

Have you ever thought about your file-server and what have you done as an IT professional to make sure your users doesn’t lose access to important company data in a longer period of time? Many people haven’t really thought about the consequences of this and how the problem easily can be avoided. I have asked some people and the answers are typically:

  • This have never been an issue, why should it break?
  • The files isn’t that important, we can wait for the repair
  • I can restore the data from backup on another server in the meantime

The solution

The solution for redundant file shares with Distributed File System (DFS). This have been around for some time starting with the File Replication Services (FRS) in Windows 2000 Server (this is still used for DC replication), but the DFS Replication in Windows 2003 R2 and higher versions is a scalable, secure and great solution for that extra file share you need if a server comes offline.

I will point out a few advantages you get with the Distributed File System here:

  • High availability file share
    You get a files hare that is replicated between multiple servers so that your file shares are always online.
  • Replicated data
    Your company data is replicated based on a schedule and the bandwidth can be controlled if you have limited bandwidth to your branch offices. Only changed data in the files are compressed and replicated so you get the most out of your available bandwidth.
  • Centralized backup
    This can be achieved if you replicate your DFS-data to your main office and backup your data here.
  • Easy migration of file servers

    If you need to migrate to another file server you can use DFS to replicate your data and make it available to users without they experience downtime.

Simple installation

The installation is very simple, and with a few minutes work you have your DFS up and running. Of course this is only the basic configuration of DFS and for more indept configuration and explanation of the features and possibilities, you need to dig more into the DFS through the Microsoft documentation for DFS.

  1. Make a new folder on a volume with enough spaces for your files and staged/conflict data (staged data is files that are replicated to this server and conflict data is files that are changed at the same time or exist on the destination server)
  2. Do the same task for your second fileserver (this can be on the same network or a branch office)
  3. Install the Distributed File System from Add/remove Windows Components
  4. Start the DFS Management Console (Not the Distributed File System console if that exists. That is the old DFS!)

For the configuration you need to know a few basic things about DFS to set up your environment correctly for redundancy.

This is the name your DFS gets on the network. You need multiple namespace servers defined to make sure your clients can access the file shares.

The folders are simply links to folder-targets. These links to one or multiple shares on the network. If one share is offline or put in "disable folder target" the DFS automatically chooses another target.

Tips and tricks

To get started you need to know some basic information, tips or "tricks" if you want. These are my small notes for DFS and I find them useful in the scenarios I implement the Distributed File Systems in.

  • Make at least two servers available to your clients of all the following types for high availability
      • Domain Controllers (and Global Catalog servers or activate Universal Group Membership caching for branch-DC’s)
      • DNS Servers
      • DFS namespace servers
  • For branch offices you need to consider the schedule and bandwidth needed within working hours. Plan your replication well in both areas.
  • Adjust your staging area so it fits your needs (large files requires large staging areas)
  • When large file shares are replicated remember to "disable target" until the replication is completed. If you do not the clients will only see the incomplete replica.
  • Keep in mind: Permissions on files/folders are only replicated first time the file/folder is replicated. –not if these permissions change! (Whilst this is article is written)
  • Remember to edit your settings when adding a namespace server to change the path away from C:\ and make the namespace domain-based.
  • Make a maintenance schedule to check the DFS logs, replication check and staging/conflict areas

More information

You can find lots of useful information on the Microsoft website and of course other sites aswell. Here are a couple of links to get you started:





3 responses to “Make your file shares redundant with DFS

  1. Djiewan September 30, 2011 at 14:14

    i have a question. is DFS only for Windows server 2003 R2 ?
    We have windows server 2003 standard edtion SP2

    • jespermchristensen October 1, 2011 at 20:38


      The Windows 2003 Server R2 version have the improved DFSR which makes the replication more stabil and efficient.

      Today I recommend you to run Windows Server 2008 or Windows Server 2008 R2 for replication as this is the most up-to-date Microsoft solution for replicating data. The licenses are not that expensive compared to the hours/consultant time you could spend in case of a replication error situation.

      I hope this is an answer you can use 🙂

      Best regards

  2. one click file hosting February 3, 2013 at 05:49

    I love it whenever people get together and share thoughts. Great site, keep it up!

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