Installing and Configuring DFS Replication
The other part of DFS is DFS Replication. DFS Replication enables you to replicate folders between multiple servers. To allow efficient use of the network, it propagates only the changes, uses compression, and uses scheduling to replicate the data between the servers.
To enable replication between multiple targets, you first create a replication group. The replication group is a collection of servers, known as servers, each of which holds a target of a DFS folder. You need a minimum of two targets to perform DFS Replication.
When you create a DFS replication group, you designate one server as the primary member of the replication group. Files then copy from the primary member to the other target servers. If any of the files in the target folders are different, DFS Replication overwrites the other files. The primary disadvantage of using DFS Replication is that you need to have sufficient storage space available on each server that hosts the server and you need extra space so that DFS Replication can process the replication.
When using DFS Replication, you should keep in mind the following limitations:
- A replication group can have up to 256 members with 256 replicated folders.
- Each server can be a member of up to 256 replication groups, with as many as 256 connections (128 incoming and 128 outgoing).
- A member server can support up to 1 TB of replicated files.
- You can have up to 8 million replicated files per volume.
DFS Replication is not a replacement for backups. If a file gets deleted, changed, or corrupted on one target server, it will most likely be deleted, changed, or corrupted on the other target servers. Therefore, you still need to use backups to provide data protection and recovery.
INSTALLING DFS REPLICATION
DFS Replication is another server role, similar to DFS Namespace. Therefore, you would use Server Manager to install DFS Namespace.
To install DFS Replication, perform the following steps:
- Open Server Manager.
- At the top of Server Manager, select Manage and click Add Roles and Features. The Add Roles and Feature Wizard opens.
- On the Before you begin page, click Next.
- Select Role-based or feature-based installation and then click Next.
- Click Select a server from the server pool, click the name of the server to install DFS to, and then click Next.
- Scroll down and expand File and Storage Services and expand file and iSCSI Services. Select DFS Replication. If File Server is not already installed, select it.
- If you are asked to add features to DFS Namespace, click Add Features.
- When you are back on the Select server roles page, click Next.
- On the Select features page, click Next.
- On the Confirm installation selections page, click Install.
- When the installation is complete, click the Close button.
CONFIGURING DFS REPLICATION TARGETS
When you replicate folders using DFS, you are replicating local folders on a server to another local folder on another server. The folder is most likely shared so that users can access the folder, but this is not necessary.
By default, replication groups use a full mesh topology, which means that all members replicate to all other members. If you have a simple DFS implementation consisting of two servers, there is some replication traffic between the two servers. However, by adding multiple servers to a replication group, replication traffic increases even more. Therefore, instead of using a full mesh topology, you can use a hub/spoke topology, were as one server is used to replicate to the other members, which limit the replication traffic to specific pairs of members.
When you configure DFS Replication, you can configure the following settings:
- Bidirectional or unidirectional
- Percentage of available bandwidth
- Schedule when replication will occur
By default, DFS replication between two members is bidirectional. Bidirectional connections occur in both directions and include two one-way connections. If you desire only a one-way connection, you can disable one of the connections or use share permissions to prevent the replication process from updating files on certain member servers.
Because DFS Replication often occurs over a WAN link, you have to be aware of how much traffic DFS uses and how you can configure it when replication occurs to best utilize the WAN links. Therefore, you can schedule replication to occur only during the night when the WAN links are not used as much or you can specify the bandwidth used by DFS Replication.
CREATE A DFS REPLICATION GROUP
To create a DFS replication group, perform the following steps:
- Open Server Manager.
- Click Tools → DFS Management. The DFS Management console opens.
- Right-click Replication and select New Replication Group.
- On the Replication Group Type page, select Multipurpose replication group, and then click Next.
- On the Name and Domain page, type a descriptive name for the replication group in the Name of replication group text box. Click the Next button.
- On the Replication Group Members page, click the Add button.
- When the Select Computers dialog box opens, type the name of the first server of the group and click OK.
- Repeat step 7 until all of the target servers are added to the group.
- On the Replication Group Members page, click Next.
- On the Topology Selection page, select Full Mesh, and then click Next.
- 11. On the Replication Group Schedule and Bandwidth page, click one of the following:
- Replicate continuously using the specified bandwidth. Specify the bandwidth that you want to use. The default bandwidth is Full.
- Replicate during the specified days and times. Then click Edit Schedule to specify which days and time you can replicate and the bandwidth used during those days and time.
- On the Primary Member page, specify which server acts as the Primary member. Click Next.
- On the Folders to Replicate page, click Add.
- When the Add Folder to Replicate dialog box opens, specify the local path name of the folder that you want to replicate. Do not type the UNC name.
- Click OK to close the Add Folder to Replicate dialog box.
- Back on the Folders to Replicate page, click Next.
- On the Local Path on Other Members page, select each member server listed and click Edit.
- When the Edit dialog box opens, select Enabled and type the local path on the member server. Click OK to close the Edit dialog box.
- Back on the Local Path of Public on Other Members page, click Next.
- On the Review Settings and Create Replication Group page, click Create.
- When the replication group has been created, click Close.
- If you get a Replication Delay message, click OK.
When the replication group is created, you can define the scheduled group. You can also modify the schedule after the replication group is created by right-clicking the replication group in the DFS Management console and selecting Edit Replication Group Schedule. When the Edit Schedule dialog box opens, you can select and deselect a range of time and then select the bandwidth usage.'