Data Management

EXPERT ADVICE

Simplifying Data Storage With iSCSI

Companies evaluating iSCSI (small computer systems interface protocol over the Internet) are driven primarily by the need to lower the cost of their storage infrastructure. However, adoption of iSCSI storage solutions by large enterprises has been slow.

A recent study by Aberdeen, surveying more than 140 organizations, provides evidence that iSCSI is now replacing or supplementing fibre channel and other competing technologies in all market segments, including large enterprises. Best-in-Class companies are using iSCSI to reduce overall storage costs and to simplify storage infrastructure and management.

Business Context

Since its introduction in 2003, iSCSI has been something of a slow starter in the marketplace. iSCSI is a compelling technology because it is based on an established and well-understood standard — SCSI. It can run on a company’s existing network, it uses relatively low cost hardware and does not require a dedicated infrastructure or specialized administrative expertise. For these reasons, iSCSI solutions have historically appealed to small and medium-sized businesses.

The entry cost is low enough to appeal to first-time storage area network (SAN) buyers, and solutions can be scaled incrementally to fit smaller IT budgets. On the other hand, fibre channel storage has been the mainstay of large enterprise data centers that have the infrastructure, budget and expertise to implement and manage it.

Vendor and industry expectations were that iSCSI adoption would move from the historical SMB base into the large enterprise, but this trend did not appear in our research. In fact, enterprise adoption of iSCSI dropped from 25 percent in the 2006 benchmark report to 20 percent for the current year. However, adoption by both small and medium-sized companies continued to grow, with mid-size adoption growing from 36 percent last year to 65 percent today.

Companies that implemented an iSCSI solution are primarily driven by the need to lower the cost of their storage infrastructure (51 percent) and to support a consolidation effort (43 percent). Consolidation represents a more subtle aspect of the corporate mandate to reduce storage costs, because consolidation requires more than acquisition or operational costs.

Consolidation is the result of the strategic consideration of questions, such as:

  • What applications are in use?
  • What kind of data should be stored and for how long?
  • What service levels are appropriate for different groups of users?

Thirty-eight percent of companies surveyed need to use their existing Internet protocol network. Until recently, accessing fibre channel storage was faster than iSCSI SANs, because fibre channel’s dedicated infrastructure isolates it from the corporate IP network and because fibre channel SANs use faster disk drives.

However, a combination of two major factors has made it more attractive to use iSCSI: faster networks (78 percent of respondents use 1 GB Ethernet and 15 percent are currently using 10 GB Ethernet) and strategic use of network routers. These effectively segment iSCSI SANs from general IP traffic. A full 55 percent of the respondents that do not currently use 10 GB Ethernet plan to do so in the future.

Best-in-Class Strategies

Establishing formal data management policies is a leading strategy (58 percent) for Best-in-Class companies in deploying an efficient storage infrastructure. While a formal data management policy might seem like an obvious industry best practice, many small companies (and even medium-sized companies) often don’t have the staff or budget to make this a priority.

Formal use of performance metrics is another significant differentiator between the Best-in-Class (46 percent), Industry Average (30 percent) and Laggards (14 percent).

Companies that had an existing fibre channel SAN were less likely to replace it with an iSCSI SAN (25 percent of respondents) than they were to supplement their existing infrastructure (50 percent). Similarly, 34 percent of the companies supplemented existing network attached storage (NAS) or direct attached storage (DAS), while only 28 percent replaced an existing NAS or DAS infrastructure.

Of course, all of these strategies have the operational effect of controlling costs by providing standards by which the efficiency of the storage infrastructure can be measured.

Requirements for Success

An iSCSI SAN is only one component in a storage infrastructure, but it can be a significant contributor to lowering storage costs and the overall complexity of the storage infrastructure. The storage infrastructure is in turn an important component in an IT strategy that meets or exceeds service levels while reducing operational costs, ultimately resulting in a tangible impact on profitability.

Whether a company is trying to move its storage infrastructure performance and efficiency from Laggard to Industry Average, or Industry Average to Best-in-Class, the following actions will help spur the necessary performance improvements:

  • Evaluate iSCSI adoption. iSCSI storage solutions can make a significant contribution to lowering storage costs especially when compared to fibre channel solutions.
  • Establish and improve a managed infrastructure. iSCSI solutions are considered to be easier and less expensive to manage than similar fibre channel solutions because support for iSCSI devices is built in to major operating systems and most iSCSI vendors include storage resource management (SRM) software as part of their solution.
  • Use tiered storage to increase infrastructure efficiency. Establishing a tiered storage architecture has been a successful strategy in the best performing companies.
  • Implement a virtual infrastructure. Server virtualization continues to grow in popularity and, with it, virtual storage and virtual tape libraries. iSCSI is closely identified with virtualization because iSCSI provides a cost-effective, highly scalable solution that is readily available on the corporate network.
  • Replace fibre channel with iSCSI. As you consider adding to your infrastructure or replacing older fibre channel installations, new high-speed iSCSI solutions present themselves as an attractive alternative in all sizes of enterprise.

IT organizations continue to look for ways to reduce the cost of storage while serving what seems like an ever expanding need for storage capacity. iSCSI solutions have a number of attributes that make them attractive for adoption by small and mid-size companies.

When compared with fibre channel solutions, iSCSI has a lower acquisition cost, will run on an existing IP network without needing a specialized infrastructure, and doesn’t require specialized administrative expertise. Even in large enterprises iSCSI is being seen as away to deliver an efficient storage infrastructure that serves users’ needs while maintaining the lowest cost. We expect this trend to continue.Click here to read Jeffrey Hill’s most recent benchmark report.


Jeffrey Hill is a senior research analyst in the data management and storage practice group at the Aberdeen Group. He can be reached at [email protected].

Tom Karol is a research associate in the Aberdeen Group’s technology markets area. He can be reached at [email protected].


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