Today’s enterprise storage managers are responsible for a multi-vendor storage environment that can comprise different systems, companies, and capabilities. Throw in the exponential growth of data from the Web, compliance issues, and content-rich applications, as well as the challenges of incorporating open systems storage, and the importance of staying up-todate on the latest and greatest in storage is vital. Because current mainframe storage technology and tools are welltested and understood, as well as mature and stable, a storage manager’s expectations are that any new storage solutions need to peacefully co-exist in the current storage universe.

As many storage managers know, Fibre Channel has become one of the primary storage solutions with its speed being a key factor in its adoption. But with all the additional data that’s being generated and accessed, storage managers need to be adaptable in evaluating technologies and solutions that can dramatically alter the cost of their storage systems without sacrificing the requirement of being enterprise-ready.

As one of the fastest growing areas in storage, iSCSI, the storage networking protocol, started out promising affordable Storage Area Networks (SANs) for Small and Medium-Size  Businesses (SMBs). Three years ago, the iSCSI standard was ratified, resulting in the first pure-iSCSI product offerings that are easy to use, sophisticated and reliable, enterprise-class networked storage solutions. Fortune 500 companies are incorporating the technology into their primary storage arsenal. iSCS I-based solutions are providing data to strategic applications such as email, Enterprise Resource Planning (ERP), Customer Relationship Management (CRM), student information systems, digital media archives and data-intensive geosciences applications for oil and gas exploration, for example.

To assess the impact iSCS I-based solutions have made so far, consider that, in the last two years, the industry has seen complete support for all the major operating systems, a variety of iSCSI Host Bus Adapter (HBA) offerings, multi-pathing solutions, cluster support, SAN boot, enterprise backup integration, and next-generation data services. While storage system vendors evolved these capabilities into Fibre Channel over the years, the interest in and demand for iSCSI-based products has accelerated the process to let storage managers evaluate and prepare for the time that iSCSI, Linux, and IP-attached storage become common on the mainframe.

As a result, serious storage deployments have been built with iSCSI, and the word has spread. Large Fibre Channel SAN systems storage vendors have to balance the capability and speed of their systems with the negatives of their expense and management complexity. Most storage managers ultimately want and need a modular, enterprise-ready storage system that will provide the reliability, performance, and features of Fibre Channel systems, but without the complexity and high cost of ownership.

What storage managers need to look for now is the best storage solution for the job; this means a redundant, highly reliable, and intelligently managed system that offers either a viable alternative to high-cost complicated systems or a counterpart to an existing storage infrastructure. iSCSI is a good choice for systems with thousands of deployments and for data centers that have Fibre Channel but want to link these systems over long distances. Organizations of all sizes are building centralized SANs on the order of 10 to 100TB and entrusting them with strategic application data. These businesses look for:

  • Reliability and security
  • No single-point-of-failure design
  • Five nines availability (99.999 percent uptime)
  • Modular scalability
  • Sophisticated enterprise storage management and protection features such as snapshots and replication.

Companies of all sizes are asking for a real SAN that provides all the enterprise benefits of Fibre Channel SANs, but without the complexity, expensive maintenance agreements, and costly upgrades.

Selecting iSCSI SANs

Currently, two distinct iSCSI product categories have emerged: inexpensive SAN systems for SMBs and enterprise-ready SANs that can complement existing Fibre Channel implementations. The midrange enterprise market was much more interesting with systems approaching enterprise capacity and functionality. The most successful of the midrange systems vendors offer a robust, enterprise-ready SAN solution that uses the iSCSI protocol to make storage simpler, more scalable, and more easily integrated into the enterprise.

On the low-end of the market, there are a variety of low-cost disk enclosures with iSCSI connectivity. More PC than storage system, these systems, while offering SAN solutions at a low price point, lack enterprise functionality and reliability.

The benefits of storage consolidation into SANs has been clearly established; affordable, easy-to-manage SAN technology makes life easier. iSCSI fits the need because it’s based on Ethernet, the standard networking protocol for all enterprises.

All the large storage vendors have felt compelled to introduce some flavor of iSCSI into their product lineup. While these vendors eagerly promote their iSCSI products and strategies, they’re careful to position their iSCSI devices at the low-end of the market to protect their high-end Fibre Channel business.

While working to establish a viable position on iSCSI, Fibre Channel vendors introduced lower-cost Fibre Channel systems for the entry-level and midrange segment to win some of the midrange market that iSCSI successfully penetrated. For the most part, the iSCSI storage systems introduced by established vendors were designed as secondary storage solutions. They were stripped of just enough enterprise features, such as scalability, redundancy and data replication, to perpetuate the perception that Fibre Channel is the only viable enterprise solution.

What Customers Really Want

Today, iSCSI is successful because customers are asking for it primarily as a robust, lower-cost, simpler-to-manage alternative to Fibre Channel. In a mainframe- oriented enterprise, looking at iSCSI as an element in the existing storage mix can generate significant benefits in cost reduction, staff allocation and technical flexibility, all while providing the storage management features expected in a mainframe environment.

Moreover, there’s a burning need for an alternative to Fibre Channel SANs, but iSCSI connectivity alone isn’t the answer. Much of the market discussion to date has focused on the protocol. As new, high-performance Serial Attached SCSI (SAS) drives find their way into the market in iSCS I-based systems, there’ll be even more need for and acceptance of the system in the enterprise.

Now that IT managers have realized iSCS I can serve as a connectivity technology of choice for enterprise systems, they’ll evaluate iSCS I and Fibre Channel systems side-by-side to choose the best combination SAN for their environment. Anyone seriously considering consolidating storage in a centrally managed pool needs more than an appliance; they need an enterprise- quality system with data center management tools that traditionally have been available only in high-end storage solutions. Z