Just about every organization has the same approach to file services. This approach almost always includes a single point of failure or in larger organizations multiple single points of failure. These single points of failure are the file servers themselves. For the most part file services are completely overlooked when it comes to upgrades and restructuring, outside of a basic storage upgrade.This is part 1 in a 2 part series.

• Part I - DFS Namespaces
• Part II - DFS Replication

Distributed File System is a Microsoft Windows Server Role, now while DFS has been around for some time this article pertains to DFS in Windows Server 2003 R2 and Windows Server 2008. DFS is actually two separate components:

• DFS Namespaces
• DFS Replication - We will be discussing this in part 2.

DFS Namespaces allows you to create a logical representation of your entire file services infrastructure. Because of this we are able to give users one single location for all files, then we are able to bring new hardware in for additional storage as well as replacement. There are two types of namespaces, Domain-based DFS and Standalone DFS.

Standalore DFS stores the DFS configuration on the local machine, while Domain-based DFS stores its configuration in the Active Directory. Domain-based DFS provides many advantages over a Standalone DFS, however it would require Active Directory, so if you do not have Active Directory than you would either need to deploy it or use a Standalone DFS.Advantages of using Domain-based DFS:

• Ability to configure multiple namespace servers, allows for a redundant environment.
• Active Directory Sites are used to determine the closest locations to the end user.
• Namespace name remains the same regardless of how many servers have been replaced/added/removed.

Windows Server 2003 Standard Edition R2 has a native limitation of 1 domain or standalone namespace per server. You can get around this limit by using an higher edition such as Enterprise or Datacenter which does not have this limit. Microsoft has changed position on this particular limitation and has released a hotfix that will remove the limitation of domain-based namespaces, standalone namespaces will still have a limit of one per server. Now when configuring a Domain-based DFS you will be asked to define the namespace. Your namespace will consist of your domain name and your DFS Root. With a Standalone DFS your namespace will consist of the server name and the DFS Root. So for example if I created a Domain-based DFS for my domain \\allanglesit.com\files\ it would look something like this. If I wanted instead to use a Standalone DFS then it would look something like this \\fileserver1.allanglesit.com\files\.

So we have decided to implement the Domain-based DFS as described above. The next step would be to prep your file servers to take part in DFS. When configuring a DFS member I like consolidating the storage on a single partition then breaking it up as needed using quotas with hard limits (so that I can create the illusion of exclusive space, however be able to expand instantly by removing or adjusting the quota) this process is outside the scope of this article. Please comment if this would be a useful article to include in the future. On fileserver1 and fileserver2 I have created a D:\ volume with a physical capacity of 300GB then I created a folder D:\DFS\ which I shared as DFS$ giving share permissions to everyone full control - NTFS permissions are setup with only the appropriate users getting read only (write permissions will be defined at a lower level).

Next we need to define the folders that users will need. So the Sales department will have a file store on fileserver1 while the IT department will have one on fileserver2. After creating both folders you will notice that nothing is visible when connecting to each servers UNC. We do this to control how the users get to their data. That way they will get the benefits of the DFS.

Once we are done creating all of the locations that we will be combining we create the folder targets in DFS using the DFS Management snap-in. When creating a folder target we must provide a name (which will be the name of the folder visible to the users) and the path (this path can be \\server\share or \\server\share\path\) in our case we will be defining 2 folder targets as follows:

name: Sales

path: \\fileserver1.allanglesit.com\DFS$\Sales\

name: IT

path: \\fileserver2.allanglesit.com\DFS$\IT\

When users connect to the DFS \\allanglesit.com\files\ they will now see 2 subfolders Sales and IT which will lead them to 2 different servers (which as we will find out in part 2 are in 2 different sites).

In part 2 we will be discussing the second component of DFS which is DFS Replication.