Use DFS Replication for Resource Pools

As mentioned earlier, DFS replication (DFSR) is an ideal tool to provide fault tolerance for the VSOs supported by your resource pools. Since a VSO is nothing but a series of files on a server, you can rely on DFSR to provide a second line of defense for the protection of your virtual service offerings. DFSR can replicate the contents of the virtual hard disk drives that make up your VSOs. In the event of a failure at one site, you can simply use the copied VSO in the second site to restart the service and ensure your end users are up and running. It is important for you to understand how to set up DFSR on Server Core.

First, begin by installing the DFSR component on your server:

This adds the required components to run DFSR. Make sure you install this component on each host server, both in the source site and in the target or disaster recovery site. Next, configure replication groups:

dfsradmin RG New /rgname:"ReplicationGroupName" /rgdesc:"Description"
dfsrAdmin RG Set Schedule full /RGName:"ReplicationGroupName"
dfsradmin member new /rgname:"ReplicationGroupName" /memname:FirstServerName
dfsradmin member new /rgname:"ReplicationGroupName" /memname:SecondServerName
dfsradmin conn new /rgname:"ReplicationGroupName" /SendMem:FirstServerName
/RecvMem:SecondServerName /ConnEnabled:true /ConnKeywords:"From First Server to
Second Server"
dfsradmin RF New /rgName:"ReplicationGroupName" /RfName:FolderName
dfsradmin Membership Set /RgName:"ReplicationGroupName" /RfName:FolderName
/MemName:FirstServerName /LocalPath:D:\vsmachines /MembershipEnabled:true
/StagingPath:E:\staging /StagingSize:1000 /CDSize:350 /IsPrimary:true

Where ReplicationGroupName is the name of your replication group and FirstServer and SecondServer are the names of the servers in the group. FolderName is the name of the folder to be replicated. For example, you could store all of your VSOs into a folder named D:\vsmachines.

The first command creates the replication group. The second adds the default schedule. The third and fourth add two servers to the group, and the fifth command creates the connection object from server one to server two. The sixth command identifies the folder to replicate. In this case, it could be VSMachines. The last command sets server one as the primary source for the replication.

TIP: For a short document describing the DFSRADMIN.EXE command, go to www.microsoft.com/ downloads/details.aspx?familyid=49caf978-49e9-4eb6-9cc9-72b5dd160505&displaylang=en.

To troubleshoot DFSR connections in Server Core, rely on the DFSRDIAG.EXE command. Repeat these commands on each host server you want to protect.

TIP: You do not need to match replication servers on a one-to-one basis. For example, you can have ten host servers protected by only five in the disaster recovery site. It is important that you understand that disaster recovery sites do not need to have the same operating levels as production environments. Keep this in mind as you prepare your replication strategies.