Virtual Fibre Channel

Existing technologies often present obstacles when considering the migration of your server
workloads into the cloud. An example of this might be if you have an AlwaysOn failover cluster instance running on SQL Server 2012 that’s configured to use a Fibre Channel SAN for high performance. You’d like to migrate this workload into the cloud, but Hyper-V in
Windows Server 2008 R2 does not support directly connecting to Fibre Channel from within VMs. As a result, you’ve postponed performing such a migration because you want to protect your existing investment in expensive Fibre Channel technology.
Virtual Fibre Channel removes this blocking issue by providing Fibre Channel ports within the guest operating system of VMs on Hyper-V hosts running Windows Server 2012. This now allows a server application like SQL Server running within the guest operation system of a VM to connect directly to LUNs on a Fibre Channel SAN.
Implementing this kind of solution requires that the drivers for your HBAs support Virtual Fibre Channel. Some HBAs from Brocade and QLogic already include such updated drivers, and more vendors are expected to follow. Virtual Fibre Channel also requires that you connect only to LUNs, and you can’t use a LUN as boot media for your VMs.
Virtual Fibre Channel also provides the benefits of allowing you to use any advanced storage functionality of your existing SAN directly from your VMs. You can even use it to cluster guest operating systems over Fibre Channel to provide high availability for VMs. See Chapter 3 for more information about high-availability solutions in Windows Server 2012.
Note that VMs must use Windows Server 2008, Windows Server 2008 R2, or Windows Server 2012 as the guest operating system if they are configured with a virtual Fibre Channel adapter. For more information, see the topic “Hyper-V Virtual Fibre Channel Overview,” athttp://technet.microsoft.com/en-us/library/hh831413.aspx.

SMB 3

Windows Server 2012 introduces SMB 3, version 3 of the Server Message Block (SMB)
protocol to provide powerful new features for continuously available file servers. SMB is a network file sharing protocol that allows applications to read and write to files and to request services from services over a network. (Note that some documentation on TechNet and
MSDN still refer to this version as SMB 3.)
The improvements in SMB 3 are designed to provide increased performance, reliability, and availability in scenarios where data is stored on file shares. Some of the new features and enhancements in SMB 3 include:

■ SMB Direct Enables using network adapters capable of Remote Direct Memory Access (RDMA) such as iWARP, Infiniband, or RoCE (RDMA over Converged Ethernet) that can function at full speed and low latency with very little processor overhead on the host. When such adapters are used on Hyper-V hosts, you can store VM files on a remote file server and achieve performance similar to if the files were stored locally on the host.

SMB Direct makes possible a new class of file servers for enterprise environments, and the new File Server role in Windows Server 2012 demonstrates these capabilities in full. Such file servers experience minimal processor utilization for file storage processing
and the ability to use high-speed RDMA-capable NICs including iWARP, InfiniBand, and RoCE. They can provide remote storage solutions equivalent in performance to Fibre Channel, but at a lower cost. They can use converged network fabrics in datacenters and are easy to provision, manage, and migrate.

■ SMB Directory Leasing Reduces round-trips from client to server because metadata is retrieved from a longer living directory cache. Cache coherency is maintained as clients are notified when directory information changes on the server. The result of using SMB Directory Leasing can be improved application response times, especially in in branch office scenarios.

■ SMB Encryption Enables end-to-end encryption of SMB data to protect network traffic from eavesdropping when travelling over untrusted networks. SMB Encryption can be configured either on a per-share basis or for the entire file server. It adds no cost overhead and removes the need for configuring IPsec and using specialized encryption hardware and WAN accelerators.

■ SMB Multichannel Allows aggregation of network bandwidth and network fault tolerance when multiple paths become available between the SMB client and the SMB server. The benefit of this that it allows server applications to take full advantage of all available network bandwidth. The result is that your server applications become more resilient to network failure.

66 Chapter 2 Foundation for building your private cloud

SMB Multichannel configures itself automatically by detecting and using multiple network paths when they become available. It can use NIC teaming failover but doesn’t require such capability to work. Possible scenarios can include:

■ Single NIC, but using Receive-Side Scaling (RSS) enables more processors to process

the network traffic

■ Multiple NICs with NIC Teaming, which allows SMB to use a single IP address per team

■ Multiple NICs without NIC Teaming, where each NIC must have a unique IP address and is required for RDMA-capable NICs

■ SMB-specific Windows PowerShell cmdlets Provides Windows PowerShell cmdlets and WMI objects to manage SMB file servers and SMB file shares.

■ SMB Scale Out Allows you to create file shares that provide simultaneous access

to data files with direct I/O through all the nodes in your file server cluster. The result is improved use of network bandwidth and load balancing of the file server clients, and also optimization of performance for server applications. SMB Scale Out requires
using CSV version 2, which is included in Windows Server 2012, and lets you seamlessly increase available bandwidth by adding cluster nodes.

■ SMB3 Secure Dialect Negotiation Helps protect against man-in-the-middle attacks, where eavesdroppers attempt to downgrade the initially negotiated dialect and capabilities be-tween an SMB client and an SMB server.

■ SMB Transparent Failover Allows administrators to perform hardware or software maintenance of nodes in a clustered file server without interruption to server applications storing their data on file shares. If a hardware or software failure happens on a cluster node, SMB clients will reconnect transparently to another cluster node with no interruption for server applications storing data on these shares.

SMB Transparent Failover supports both planned failovers (such as maintenance operations) and unplanned failovers (for example, due to hardware failure). Implementing this feature requires the use of failover clustering, that both the server running the application and the file server are running Windows Server 2012, and that the file shares on the file server have been shared for continuous availability.

■ VSS for SMB file shares Allows SMB clients and SMB servers supporting SMB 3.0 to

take advantage of the Volume Shadow Copy Service (VSS) for SMB file shares.
The implementation of SMB 3 in Windows Server 2012 also includes new SMB performance counters that can provide detailed, per-share information about throughput, latency, and I/O per second (IOPS). These counters are designed for server applications like Hyper-V and SQL Server, which can store files on remote file shares to enable administrators to analyze the performance of the file shares where server application data is stored.

Benefits for Hyper-V

These new capabilities of SMB 3 mean that Hyper-V hosts can store VM files, including the configuration, VHD, and snapshots in file shares on Windows Server 2012 file servers. You can implement this kind of solution for stand-alone Hyper-V servers. You also can implement it
for clustered Hyper-V servers where file storage is used as shared storage for the cluster.
The benefits that enterprises can experience from these scenarios include simplified provisioning, management and migration of VM workloads, increased flexibility, and reduced cost.

SMB and Windows PowerShell

You can view and manage many SMB 3 capabilities by using Windows PowerShell. To see what cmdlets are available for doing this, you can use the Get-Command cmdlet, as shown in Figure 2-17.

FIGURE 2-17 Windows PowerShell cmdlets for managing SMB features and infrastructure.

For example, Figure 2-18 shows how to use the Get-SMBServerConfiguration cmdlet to determine whether SMB Multichannel is enabled on a file server running Windows Server 2012.

FIGURE 2-18 Viewing the configuration settings of the SMB server.

For more information about the new Windows PowerShell cmdlets for managing SMB

File Servers and SMB File Shares, see the post titled “The basics of SMB PowerShell, a feature of Windows Server 2012 and SMB 3.0” on Jose Barreto’s blog at http://blogs.technet.com/b/ josebda/archive/2012/06/27/the-basics-of-smb-powershell-a-feature-of-windows-server-2012- and-smb-3-0.aspx.

For more information about SMB Multichannel, see the post titled “The basics of SMB Multi-channel, a feature of Windows Server 2012 and SMB 3.0” on Jose Barreto’s blog at http://blogs.technet.com/b/josebda/archive/2012/06/28/the-basics-of-smb-multichannel-a- feature-of-windows-server-2012-and-smb-3-0.aspx.

For more information about VSS for SMB File Shares, see the post titled “Windows Server
2012 and SMB 3.0—VSS for SMB File Shares” on Jose Barreto’s blog at http://blogs.technet
.com/b/josebda/archive/2012/06/30/windows-server-2012-and-smb-3-0-vss-for-smb-file-
shares.aspx.
For more information about SMB Encryption, see the post by Obaid Farooqi titled “Encryption in SMB3” on the Microsoft Open Specifications Support Team Blog at http://blogs.msdn.com/b/openspecification/archive/2012/06/08/encryption-in-smb3.aspx.

For more information about SMB3 Secure Dialect Negotiation, see the post by Edgar Olougouna titled “SMB3 Secure Dialect Negotiation” on the Microsoft Open Specifications Sup-port Team Blog at http://blogs.msdn.com/b/openspecification/archive/2012/06/28/smb3- secure-dialect-negotiation.aspx.

Windows Server 2012: Enabling the “Storage LAN”

veryone is familiar with the concept of a SAN. Typically a very expensive disk array, attached to some very expensive fiber channel switches. Then one or more

Fibre Channel cables run from the switch to a fairly expensive dual-port HBA.

SANs have long been one of the most expensive and difficult things to manage in the datacenter. Enterprise organizations invest heavily in storage and invest heavily in storage training. Your average Windows administrator is not equipped with

the skills required to manipulate and design enterprise storage, yet every server of consequence is typically directly connected to enterprise storage. Configuring HBAs, LUN mapping, and similar tasks is often per-server, manual, and reserved for the select few who have the extra training and experience.

Virtualization improves this, as long as your servers use either iSCSI (which is often regarded as a poor man’s SAN), or are self-contained in a VHD. Mapping SAN storage, directly into VMs, is not trivial, quick, or easy.

Windows Server 2012 with the introduction of the continuously available file server, and SMB 3 change this. It allows Windows administrators to disconnect themselves from the traditional SAN and create a new breed of “Storage LAN.” Consider this example. In the past, when you deployed a new SQL Server instance, you did one of the following:

■ Deploy to a physical host. Install an HBA. Create a SAN LUN. Run the fiber to the

server. Map the LUN to the host, and then use the storage for SQL Server.

■ Deploy to a VM. Store the VM in a VHD which was stored on, most often a CSV

volume, which was on a LUN previously mapped to the host.

■ Deploy to a VM. Install an HBA. Create a SAN LUN. Run the fiber to the server. Map

the LUN to the host, and then pass the LUN to the VM as a pass-through disk. Windows Server 2012 changes this by allowing you to replace much of your storage

infrastructure with traditional Ethernet. LUNs are replaced with file shares. Here’s

what this new architecture looks like.

You still have your high-end storage solution; however, instead of running complex storage fabric to every host, you run the storage fabric to a set of high-performance file servers. These file servers present the storage as highly available file shares to be used by any server.

Next, you create an Ethernet segment between your storage file servers and

your application servers leveraging technologies such as 10 GB Ethernet (which is standard on most high-end servers), or if you need extremely fast performance (and your storage arrays can even keep up with it), RDMA.

When new servers are brought online, instead of running fiber, provisioning LUNs,

and involving your storage administrators, you can simply provision a share or use an existing one. This change allows a Windows administrator to use the skills and tools they already have, and are familiar with, to present highly available, high-performance storage to any application server. You can deploy application workloads such as SQL, and even Hyper-V, which leverage the performance and reliability of enterprise SAN storage without needing to be directly connected to the enterprise SAN fabric.

With technologies such as transparent failover, cluster-aware updating, and storage spaces with thin provisioning, you can now plan for what you need tomorrow, but deploy and manage with what you have today.

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