Is it time for SMB storage area networks?

A Microsoft storage executive makes the case for smaller businesses moving to SANs—Fibre Channel or iSCSI.

By Claude Lorenson

The ratification of the iSCSI protocol last year brought on a flurry of discussions, opinions, and initiatives centered on delivering the promises of storage area networks (SANs) to small and medium-sized businesses (SMBs). And storage vendors are rushing into this "new" area in hopes of realizing new revenues.

An SMB SAN can be used in many environments, ranging from departments in large corporations to companies with anywhere from 100 to 1,000 users. The common denominator in these environments is a relatively small number of servers on a SAN—generally, between three and 20.

SMBs have always needed better storage utilization, scalability, and backup, but until recently the costs associated with deploying SANs have been prohibitive. According to Cisco's research, SANs have penetrated only about 10% of the SMB market.

Although the benefits of pooling storage devices with SANs are just as compelling for smaller businesses as they are for larger ones, SANs remain far more prevalent in large enterprises.

Fibre Channel SANs can be complex and expensive and require specialized expertise. SMBs often do not have storage administrators. The SMB IT administrator, who usually has other jobs in the company, is generally the person who handles storage provisioning for applications. Many of these administrators are unfamiliar with SAN technologies and, for example, the differences between Fibre Channel and iSCSI.

However, SMB IT administrators know that whenever they need to add disks to their direct-attached storage (DAS) servers they have to halt services to their users. They also know that the proliferation of data generated by applications such as e-mail and digital imaging is taxing their backup capabilities. What they sometimes do not know is that a SAN can help solve these problems.

An SMB has the same storage needs as large data centers, including scalability for applications, centralized management, and faster backup. On the business side, companies of all sizes need to provide business continuity solutions and are required to comply with regulations pertinent to their industries.

Reducing total cost of ownership (TCO) is another key issue for all businesses. These needs are no different in a small business running e-mail and database applications for 200 users than they are for a data center running the same types of applications for 10,000 users. What is different is the scale of the organization and the level of storage expertise in the IT staff.

According to research from AMI-Partners, SMBs account for only 20% of all storage spending while representing 40% of all IT spending. However, with increased security needs, compliance regulations, and archiving requirements, this situation is changing rapidly.

Prior to the availability of IP SANs based on iSCSI, the capital investment and expertise required to install Fibre Channel network components—host bus adapters (HBAs), cabling, and switches—was substantial. Also, redundant configurations, while ensuring continuously available data, add considerably more cost and complexity. Furthermore, the costs associated with Fibre Channel expertise and training are too high for many small businesses. Even though the typical IT administrator understands backup, adding disks to servers, and managing the provisioning of applications in a DAS environment, those tasks take on a different level of complexity with SANs (Fibre Channel or iSCSI).

Since iSCSI is generally recognized as being easier to deploy than Fibre Channel, it has been key to the discussion about SANs for SMBs. Additionally, iSCSI uses a protocol that is familiar to most LAN administrators.

The iSCSI protocol, which can be used with inexpensive IP components, is beginning to emerge as a low-cost alternative to Fibre Channel. With the price of iSCSI hardware (targets, NICs, HBAs, and switches) getting to a level that is acceptable to SMBs, those smaller companies are beginning to experiment with IP SANs, primarily for data backup. Ironically, iSCSI has played a big role in influencing Fibre Channel vendors to reduce prices and make their products easier to use.

Storage spending is expected to increase approximately 18% to 20% per year in the SMB space over the next few years. Fibre Channel vendors now recognize that in order to capitalize on the SMB market, SAN deployments must be simple, inexpensive, and easy to use. Each of these attributes is necessary, but not sufficiently compelling individually, to make an SMB deploy a SAN. All three attributes must be present to make SANs attractive to SMBs.

With the ratification of the iSCSI protocol and new operating systems with built-in services for simpler management tools (e.g., Microsoft Windows Server 2003 Virtual Disk service and Volume Shadow Copy service), SMBs that want to expand beyond traditional DAS architectures have a new alternative.

At the same time, Fibre Channel vendors are providing new tools that can make Fibre Channel SAN deployments in small business environments a reality. For example,

  • Simpler methods for installing HBAs in servers;
  • Plug-and-play SAN connectivity kits;
  • Built-in tools that SMB administrators can use to provision storage arrays;
  • Built-in drivers and troubleshooting tools that simplify device deployments; and
  • Lower prices for storage arrays, switches, and HBAs.

Most of the new tools for SMB SANs are designed for Windows environments. In the SMB space, Microsoft Exchange Server is the dominant e-mail application and Microsoft SQL Server is often the preferred database application. Windows Server 2003 is more SAN friendly than previous versions of Windows, which facilitates running these applications on a SAN. With built-in iSCSI support in Windows Server 2003, tools like Virtual Disk service, Volume Shadow Copy service, and other storage services, it is now easier for small businesses to cost effectively migrate from DAS to SAN architectures.

Microsoft Windows Server 2003 incorporates a number of features that simplify operating system integration with a SAN, including the following:

  • Virtual Disk Service (VDS) for simpler storage provisioning;
  • Volume Shadow Copy Service (VSS) for creating point-in-time copies;
  • Storport for better HBA management;
  • Multi-path I/O (MPIO) for fail-over and load balancing; and
  • Fibre Channel Information Tool for dynamically gathering SAN component information.

With the availability of a built-in iSCSI initiator and support for iSNS in Windows Server 2003, it is relatively simple to build an IP SAN for small businesses that want to leverage their existing networking infrastructure and benefit from iSCSI advantages such as long-distance capability, protocol familiarity, and low cost.

Last year, Microsoft developed a program to ensure interoperability of iSCSI components while making it easier for service providers to deliver a standard integrated infrastructure. Software developers can optimize their products to work on a standard Windows infrastructure, and Microsoft is also qualifying iSCSI hardware for Windows environments.

There are a variety of iSCSI products available today—including software drivers, network adapters, and HBAs—and the market is now shifting to iSCSI targets (e.g., disk arrays and tape libraries). A number of vendors have already released products that connect iSCSI to Fibre Channel and SCSI arrays, allowing users to preserve existing investments.

By leveraging built-in Windows tools, software and hardware providers can focus their R&D investment on product innovations. Windows Storage Server technologies (including a SNIA-compliant HBA management API, VDS, VSS, Distributed File System, MPIO, and iSCSI) enable host- and hardware-based solutions, making it easy to support users' legacy architectures and providing configuration flexibility.

For example, a storage hardware vendor can write a hardware provider that translates the VDS general-purpose interface into specific instructions for the hardware. VDS acts as a coordination service that supports multiple hardware providers. Then, when an IT administrator purchases storage devices from different vendors (each device contains its own VDS hardware provider), Windows Server 2003 can manage the devices.

MPIO eliminates the need to develop a multi-path solution for every patch, HBA/switch firmware upgrade, and array. Windows Storage Server 2003 also has a comprehensive set of hardware device drivers for PCI cards, tape drives, and CD/DVD drives.

With these options, IT administrators can choose the solution that best meets their storage architecture, scalability, and backup requirements at affordable price points. Also, the renewed ease-of-use focus from Fibre Channel vendors makes the management case for migrating to SANs more compelling.

In short, small businesses now have more choices for migrating away from DAS to networked storage, whether it's a Fibre Channel or iSCSI SAN.

For more information and interactive discussions about SANs for SMBs, check out www.microsoft.com/windowsserversystem/storage/ community/default.mspx.

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Claude Lorenson is a technical product manager at Microsoft (www.microsoft.com).

This article was originally published on May 01, 2004