Create a Basic Scale-Out File Server (SOFS)

Posted on July 29, 2013 by Aidan Finn in Backup & Storage with 0 Comments

In this post we will show you how to create a scale-out file server (SOFS) to share scalable and transparent failover storage via SMB 3.0. This lab will use Windows Server 2012 R2 but the instructions also apply to Windows Server 2012.

(If you need to do some catching up, check out our previous articles on Windows Server 2012 SMB 3.0 File Shares: An Overview and Windows Server 2012: SMB 3.0 and the Scale-Out File Server.)

Scale-Out File Server and the Environment

The design of the SOFS nodes in this example is as shown in the below diagram. Illustrated is a single node of the SOFS cluster. There are four NICs which are used for two roles.

  • Management (Management1 and Management2): Two NICs are teamed and connected to a VLAN on the general server network. A single IP address is assigned to the team interface. This is the connection that is used to manage the cluster.
  • SMB 3.0 and cluster communications (SMB1 and SMB2): A pair of non-teamed NICs will be used to handle SMB 3.0 connections and cluster communications (such as heartbeat and redirected IO). Each of these NICs is on a different VLAN, which is a requirement when mixing SMB Multichannel with failover clustering. These NICs are on a dedicated storage network, probably isolated from the general server network. Now, don’t get confused – these are two simple NICs that will be used by the cluster and SMB 3.0 protocols. There are no virtual NICs in this converged networks/fabrics design.

Create Scale-Out File Server: SOFS Node Network Design

It is the SMB NICs that you would consider using Remote Direct Memory Access (RDMA) networking for SMB Direct. It isn’t essential, but SMB Direct does give better performance, especially if your SMB 3.0 workload reaches larger levels. You will implement QoS for the cluster and SMB 3.0 protocols. How this is done depends if you are using SMB Direct or not. RDMA requires Datacenter Bridging (DCB) QoS rules, and this requires support in your NICs and end-to-end SMB connection switches. You can implement simpler per-protocol QoS rules that are applied by the OS Packet Scheduler if you will not be using RDMA/SMB Direct.

The cluster is created, and one CSV has been created for each (two in this example) node in the file server cluster. The CSVs can reside on block storage or on Storage Spaces.

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Prepare Active Directory (AD)

An organizational unit (OU) has been created to store the computer objects of the SOFS cluster. This is to allow us to create restricted delegation of security within AD. You need to delegate security permissions to allow creation of computer objects to the SOFS cluster’s computer object. Failing to do this will create the most common failure in SOFS deployment: The SOFS role will attempt to start on the cluster and will fail, reporting that it cannot create the computer object for the SOFS role in AD.

Another common error is one you see in a lab environment where the same SOFS is constantly being deployed and destroyed. You need to make sure that the SOFS role’s A records have been deleted from DNS.

Cluster Networking

By default, only a network with a default gateway will be selected for Cluster usage and Client Connectivity. The SOFS nodes must be configured to use the SMB NICs (shown as Cluster1 and Cluster2 below) for client connectivity. These are the NICs that application servers (such as Hyper-V) will connect to for SMB 3.0 data streaming. Note that SMB constraints will be enabled on application servers to limit SMB Multichannel to their NICs that are on this private SMB network.

Create Scale-Out File Server: Cluster Networking

Edit the properties of each SMB NIC and check the box to Allow Clients To Connect Through This Network. This will create a warning that you can ignore in the case of a SOFS; the SOFS role will actually create a new computer object in Active Directory. That object will register DNS records for itself using each of the IP addresses of the nodes themselves. The SOFS does not use an IP address of its own. SMB clients (application servers) will use these DNS records to find the SOFS, and SMB constraints will restrict those SMB clients to just the NICs on the private network.

Create Scale-Out File Server: Cluster Properties

Create the SOFS Role

  • Browse to Roles in Failover Cluster Manager and click Configure Role. Select the File Server role.

The next step is very important. There are two kinds of clustered file server:

  • File Server for general use: This is the traditional active/passive file server. This should be used for end-user file shares and never used for application file shares.
  • Scale-Out File Server for application data: This is the active/active file server role that was introduced in Windows Server 2012. This should be used for application file shares and never use for end-user file shares. You can store file server virtual machines in this share.

Create Scale-Out File Server: HA Wizard

The next step is to name the Client Access Point (CAP). The CAP is the computer object that will be created in AD for Kerberos authentication and authorization, and the fully qualified domain name (FQDN) will be registered in DNS with the IP addresses of the nodes (NICs with client communications enabled – above). In this lab, the cluster is called Demo-FSC1.demo.internal. That is the name that is used to manage the cluster. The CAP will be called Demo-SOFS1.demo.internal. That will be the name that SMB clients (application servers) will use to connect to shares on the SOFS.

Create Scale-Out File Server: HA Wizard

The new SOFS role will be added to the cluster, and the cluster will attempt to start the role. If the role fails to start, try the following.

  • Double-check that the cluster object has “create computer” rights in the OU in which the cluster nodes and object reside.
  • Check the Cluster Events log in Failover Cluster Manager.

Create Scale-Out File Server: SOFS role

You should find a new computer object created and each client enabled NIC in the cluster has its IP registered in DNS with the A record of the SOFS CAP. Note how the two nodes (Demo-FS1 and Demo-FS2) are have also registered their overlapping A records in DNS.

Create Scale-Out File Server: SOFS role

What you have done up to now is the equivalent of setting up a SAN. The next step in a SAN is to provision LUNs; in our case, we will create shared folders in the scale-out file server.

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Creating File Shares

You need to share the storage space of the cluster’s CSVs with application servers. This is done by creating shared folders and setting their permissions.

  • Browse to the SOFS role in Failover Cluster Manager, select the SOFS, and click Add File Share. The New Share Wizard starts up.  Select the SMB Share – Applications option.

Note that it can take a minute or two for the SOFS to come online on all nodes in the cluster. This wizard will fail to launch until this happens.

Create Scale-Out File Server: file shares

  • Choose the CSV on which you want the shared folder to be stored.

Create Scale-Out File Server: file shares

  • Enter the desired name of the share. We are choosing to give it a name that is similar to the CSV disk’s name.

Note how the UNC path of the shared folder is automatically built up for you. Our SOFS CAP is called Demo-SOFS1. The share is called Virtual Disk 1. Clients will therefore connect to \\Demo-SOFS1\Virtual Disk 1. Clients connect to this single path to access this share that resides on between 2 and 8 nodes in the cluster.  SMB 3.0, DNS, and the SOFS role handle name resolution, connectivity, and failover “auto-magically.”

Create Scale-Out File Server: share wizard

  • You can choose to Encrypt Data Access. This is a good idea if your SMB traffic will go over a non-private network and other machines could snoop in on these communications. Enabling this encryption will provide you with network security.

Create Scale-Out File Server: share wizard

  • You should configure the permissions of the share in the Specify Permissions To Control Access screen.
  • Grant your application servers and application administrators (such as Hyper-V hosts, Hyper-V administrators, VMM Run-As Account) full control over the share and folder. Watch out for the unwanted default where Everyone is granted access.
  • It can take a few seconds for the cluster database to synchronize the SOFS and bring the share online on all cluster nodes. You can then test the UNC path and then start using it on your application servers.
  • On-going management of shares should be done in Failover Cluster Manager. You can select the SOFS role and see the associated shares in the lower pane of the screen. Simply right-click one and select properties to modify a share.

Create Scale-Out File Server: failover cluster manager

Best Practices for Shares

The one golden rule is to configure the permissions to be as restrictive as possible. Use security groups, even if they require member servers to be rebooted to pick up their group membership. This should only needed to be done once when a new host or applications server is brought online – consider using Live Migration to eliminate service availability downtime.

How many shares is the right number? There is no guidance yet, but you might consider the following.

  • Simple private cloud or basic virtualization: Create one CSV per node in the SOFS cluster. Create one share per CSV that is named after the CSV.
  • Complex private cloud or public cloud: Create one or two CSVs per node in the SOFS cluster. Create one or two shares per host farm that is connecting to the SOFS.
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