Windows Insider

Server Message Block 3.0: Microsoft's New Storage Model

• By Greg Shields
• 05/02/2012

UPDATE: Since this article was published in our May 2012 issue, Microsoft has renamed SMB 2.2 to SMB 3.0. The story has been changed to reflect this. -- The Eds.

Considering buying a SAN? Stop what you're doing. The world of storage is about to change and its future lies in a surprisingly familiar protocol: the Server Message Block (SMB).

For many years IT has divided storage into two distinct halves. On one side are NAS devices. Easy to install and manage, a NAS is ostensibly a file share attached to a network connection.

On the other side are SANs. With a focus "below" the level of files and folders, SANs expose block-level storage. SANs first require a connection via protocols such as Fibre Channel or iSCSI before a server can interact with storage.

People choose SANs for performance. Depending on the workload, many SANs are believed to outperform an equivalent NAS device. People also choose SANs for their flexibility.

But in a Windows shop, isn't a SAN really a NAS in disguise? Think about its total configuration: A SAN's hardware and underlying protocols exist to connect disks to a Windows server.

SANs are also notoriously complex beasts to install and operate. Their protocols and administrative tools are often vendor-specific. Managing them requires an arcane knowledge of which few can claim mastery. Load balancing and failover generally require complex configurations at both storage and server levels.

All this, just to expose a few disks to Windows.

A New Approach
That challenge is why the SMB protocol, specifically SMB 3.0 in Windows 8, might just be the future of storage. Eliminate for a minute all the technologies, and consider the high-level requirements you place on storage: You get excellent performance with low CPU overhead. Fault tolerance to ensure lost connections don't mean lost data. Load balancing to scale throughput with the number of NICs. Simultaneous access by multiple cluster hosts, with built-in arbitration for data consistency. And there's backup support that facilitates the capture of application-consistent backups.

Achieving all of this today with a SAN requires added protocols, techniques and management tools because today's SMB protocol doesn't support today's storage requirements. But why not just update the SMB protocol?

With SMB 3.0, it appears Microsoft has. This update, baked into both Windows 8 and Windows Server 2012, might just drive a wholesale shift away from SANs' complexities and to a simpler, NAS-like foundation.

Fixing Clustering
While SMB 3.0 solves many storage problems, one might wonder if Hyper-V is the motivator for this protocol investment.

I've long suggested that Microsoft's unnecessarily complex clustering architecture is a major hurdle to Hyper-V adoption. Since its inception, Windows Failover Clustering has been too difficult to construct, too difficult to use and too easy to break. SAN storage is a contributor to that complexity.

SMB 3.0 changes this game completely. With it, building a cluster requires pointing servers to a network file share. Everything else just happens. That's the dead-simple clustering experience a Hyper-V admin demands.

Assuming SMB 3.0 accomplishes everything hinted thus far, Microsoft's next challenge will be reducing the inferiority complex surrounding NAS.

NAS vendors are already fanning the flames. As Vaughn Stewart, director of Cloud Computing at NetApp, recently said, "Once you understand that NAS is every bit as capable as SAN in providing high-performance and low-latency access to virtualized data sets, then you can be free to consider the benefits of storage as a shared, networked service."

I couldn't agree more.