Overview of the File Server Role in Windows Server 8 Failover Clustering

Introduction

The next version of Windows Server has been officially dubbed and the name comes as no surprise to IT pros who have used the last three versions: It’s Windows Server 2012. My next few articles will delve into some of its new and improved features, beginning this time with an overview of the file server role in failover clustering.

In operating systems prior to Windows Server 2012, highly available file services were provided by failover cluster Client Access Point (CAP) that clients could use to connect to SMB (Server Message Block) or Network File System (NFS) shares on physical disk resources. If you deployed a shared-nothing cluster, only one node in a cluster File Server group could be online. In the event of a failure or if the File Server group was moved to another cluster node, clients were disconnected and had to reconnect when the group became available on an online node in the cluster. 
In Windows Server 2012, the File Server Role has been expanded to include a new scenario where application data (specifically Hyper-V and SQL Server) is supported on highly available SMB shares in Windows Server 2012 Failover Clustering. This is called Scale-Out File Services and uses the following:

• a new client access method using a new cluster resource type, called a Distributed Network Name (DNN)
• Cluster Shared Volumes v2 (CSVv2)
• SMB v3 improvements, which enables continuous availability and transparent failover. 

SMB v3 allows SMB connections to be distributed across all nodes in the cluster that have simultaneous access to all shares. This can make it possible to provide access with almost zero downtime.

Installing the General Use File Server Role

File servers in a cluster can be configured for general use (such as users storing files in shares) or to support application storage for Hyper-V and SQL. The General Use File Server in Windows Server 2012 is almost the same as it was in Windows Server 2008 R2. The only significant difference is that shares can be made continuously available with the help of the SMB 3.0 protocol.
The following steps show the installation options for installing the General User File Server role on a Windows Server 2012 failover cluster:

1. Click on Configure Role in the Actions pane in Failover Cluster Manager.
2. Click  Next on the Before You Begin page.
3. On the Select Role page, select the File Server role. Make sure there are no errors indicating the role is not installed on all nodes in the cluster, and click Next.

Figure 1

4. On the File Server Type page, select File Server for general use and click Next. Note that when you select this option, you have support for SMB and NFS shares, and you can also use File Server Resource Manager, Distributed File System Replication and other File Services role services.

Figure 2

5. On the Client Access Point page, enter the information for the Client Access Point (CAP) and click Next.
6. On the Select Storage page, enter a storage location for the data and click Next.
7. On the Confirmation page, read the Confirmation information and click Next.
8. On the Summary page, you can click the View Report button if you want to see details of the configuration. Click Finish.

Now that the role is installed, you can create file shares on the failover cluster.
Perform the following steps to create the file shares:

1. Click the File Server Role in the Failover Cluster Manager and in the Actions pane, click Add File Share.
2. The server configuration will be retrieved as a connection is made to the File and Storage Services Management interface.
3. The Select Profile page presents you with five options. For our purposes, you can choose either SMB Share - Basic or SMB Share - Advanced and click Next

Figure 3

4. On the Share Location page, choose a Share Location and click Next.
5. On the Share Name page, provide a Share Name and click Next.
6. On the Other Settings page, there are a number of additional share settings from which you can choose. Notice that Enable Continuous Availability is checked by default; this is to take advantage of the new SMB v3 functionality (Transparent Failover). Another new feature in SMB v3 enables you to encrypt the SMB connection without requiring the overhead of IPsec. You can find out more about SMB v3 here. Click Next.

Figure 4

7. On the Permissions page, you can configure permissions to control access (both NTFS and share permissions). Click Next

Figure 5

8. On the Confirmation page, review the information and click Create.

When the share is configured, it will appear in the Shares tab.

Figure 6
If you prefer the command line, you can also get information about the share by using the PowerShell cmdlet Get-SMBShare.
Another place you can find share information is in the File and Storage Services Management Interface in Server Manager.

Installing the Scale-Out File Server Role

The Scale-Out File Server role is new in Windows Server 2012. With the many new technologies in Windows Server 2012, you can provide continuously available file services for application data and, at the same time, respond to increased demands quickly by bringing more servers online. Scale-Out File Servers take advantage of new features included in Windows Server 2012 Failover Clustering. The key new features that are included in Windows Server 2012, which enable the Scale Out Server Role, include the following:

• Distributed Network Name (DNN) – this is the name that client systems use to connect to cluster shared resources
• Scale-Out File Server resource type
• Cluster Shared Volumes Version 2 (CSVv2)
• Scale-Out File Server Role

Note that Failover Clustering is required for Scale-Out File Servers and the clusters of Scale Out File Servers are limited to four servers. Also, the File Server role service must be enabled on all nodes in the cluster. 
SMB v3, which is installed and enabled by default in Windows Server 2012, provides several features that support continuous availability of file shares to end users and applications. It’s important to point out that Scale-Out File Servers support storing application data on file shares and that SMB v3 will provide continuous availability for those shares for the two supported applications, which are Hyper-V and SQL Server. Specific capabilities that exist as part of the new SMBv2.2 functionality include:

• SMB2 Transparent Failover – this allows all members of the cluster to host the shared resources and makes it possible for clients to connect to other members of the cluster transparently, without any perceptible disconnection on the client side.
• MB2 Multichannel – this enables the use of multiple network connections to connect to cluster hosted resources and enables the cluster members to be highly available by supporting out of the box NIC teaming and bandwidth aggregation.
• SMB2 Direct (RDMA) – this makes it possible to take advantage of the full speed of the NICs without impacting the processors on the cluster members; it also makes it possible to obtain full wire speed and network access speeds comparable to direct attached storage.

For more information about the Scale-Out File Server role, check out this link.
Perform the following steps to create a Scale-Out File Server Role:

1. Click Configure Role in the Actions pane in Failover Cluster Manager.
2. On the Before You Begin page, click Next.
3. On the Select Role page, click the File Server role. Make sure there are no errors indicating the role is not installed on all nodes in the cluster and click Next.

Figure 7

4. On the File Server Type page, select File Server for scale-out application data and click Next. Note that when you select this role, there is support only for SMB v3 shares; that is, there is no support for NFS shares. In addition, with this configuration you will not be able to use some file server role services, such as FSRM and DFS replication.

Figure 8

5. On the Client Access Point page, enter a valid NetBIOS name for the Client Access Point and click Next.
6. On the Confirmation page, review the information and click Next.
7. When the wizard completes, you can click the View Report button to see details of the configuration. Click Finish.

Now that the role is installed, you’re ready to create file shares for applications where you can place the application data.
Perform the following steps to create shared folders:

1. Click the File Server Role in the Failover Cluster Manager, and in the Actions pane, click on Add File Share.
2. The server configuration will be retrieved as a connection is made to the File and Storage Services Management interface.
3. On the Select Profile page of the New Share Wizard, choose SMB Share - Server Application for the profile and click Next.

Figure 9

4. On the Share Location page, you should see only Cluster Shared Volumes.  Select a volume where you want to place the share and click Next.

Figure 10

5. On the Share Name page, enter a Share Name and click Next.
6. On the Other settings page, note that Enable continuous availability is selected by default. Click Next.
7. On the Permissions page, you can configure permissions to control access (both NTFS and share permissions) as needed. Click Next.
8. Review the information on the Confirmation screen and click Create.

The Shares tab reflects all the shares that are configured on the CSV volumes.

Figure 11
The Distributed Network Name resource, which is part of the Scale-Out File Server role, has no dependencies on IP addresses; that means you don’t have to configure anything in advance for this to work. The reason for this is that the resource registers the node IP addresses for each node in the cluster in DNS. These IP addresses can be static IP addresses or they can be managed by DHCP. The IP address of each of the nodes in the cluster is recorded in DNS and is mapped to the Distributed Network Name. Clients then receive up to six addresses from the DNS server and DNS round robin is used to distribute the load.

Summary

In this article, we took a quick look at some of the new file server role capabilities included in Windows Server 2012. The traditional file server role continues with Windows Server 2012, but includes some nice new benefits, thanks to the new SMB v3 protocol, which provides for continuous availability and near zero downtime for file resources being hosted by the cluster. A new file services role, the Scale-Out File Server role, enables you to store application data for Hyper-V and SQL server, and is optimized for these applications that require continuous connectivity to these files over the network. Several improvements included in the SMB v3 protocol make it possible to host these files on a file server cluster and enable performance at wire speed and very close to the storage performance you can get with direct attached storage.

Author: Deb Shinder