Feature

IP SANs take their place

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Midrange storage vendors have been among the first to capitalize on iSCSI as a mechanism for networking their low-cost storage arrays. Boulder, CO-based LeftHand Networks, for example, added the IP protocol and a suite of storage management software tools to its serial ATA arrays to create an IP SAN in a box. "We provide a fully managed SAN at the cost of just the Fibre Channel storage capacity, but without the extra cost of software or Fibre Channel," says Tom Major, vice president at LeftHand Networks. The LeftHand product doesn't include a switch, which keeps the price lower than similar alternatives.

Intransa Inc., headquartered in San Jose, CA, also provides an IP SAN storage array with built-in storage management capabilities. Unlike LeftHand Networks, Intransa includes a Layer-2 Gigabit Ethernet switch. The list price for the base 3.2TB configuration is $62,500.


IP vs. FC: sample cost comparison

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COMPONENT COSTS IP FC
1Gb connector card $250 $1,000 or more
16-port 1Gb switch $15,000 $25,000
Network administrator $50,000 to $70,000 $80,000 to $100,000

The midrange approach certainly appealed to Mapics Inc., Alpharetta, GA, a developer of manufacturing software. When the company found itself managing an increasingly unwieldy set of servers and their attached storage for its core business applications, it looked for a storage consolidation option. After checking out traditional FC SAN solutions, the company turned to LeftHand Networks.

Although Mapics only needed a total of 340GB of storage, "LeftHand could give us a SAN with a terabyte of storage and RAID striping for one-third of the cost of the closest Fibre Channel SAN," says Jim Overdorff, Mapics director of enterprise technical services. The company easily added the LeftHand SAN to its existing Gigabit Ethernet backbone and directed its nine servers to the LeftHand storage. The increased traffic proved to be no problem: "We run backups at off-peak hours and have had no network throughput problems," he says.

Cost considerations
FC has fully established itself as the SAN standard in the enterprise, but it remains difficult and costly to acquire, deploy and manage. Vendor compatibility problems persist, and people with FC skills are difficult to find and cost more than IP network administrators. It costs $80,000 to $100,000 or more to hire skilled FC network people, compared with $50,000 to $70,000 for IP network administrators, says Mark Goodstein, president of Techpros, an IT recruitment firm in Needham, MA.

In addition, enterprise storage components--disk arrays, HBAs, switches, tape libraries--enabled for use with FC are more costly than their IP counterparts. An Internet search turned up 1Gb FC HBAs, for example, at $1,400 (single retail purchase), compared to 1Gb Ethernet adapters at $500 or less. At the switch level, FC fabric switches run from $700 to $950 per port, and director-class switches run from $1,800 to $2,400 per port, according to a spokesman at a major switch vendor. A Gigabit Ethernet switch for IP costs at least one-third less. A slower 10/100 Ethernet switch can be acquired for a few hundred dollars or less.

Interoperability problems still exist in FC SANs. Although FC component compatibility and interoperability problems are diminishing as a result of endless interoperability plug-fests and continuous OEM compatibility testing, they haven't gone away completely. IP component interoperability, on the other hand, hasn't been an issue for years.

Cost was a major driver when the Carlson Companies in Minneapolis decided to deploy a combination Nishan FCIP SAN. Carlson operates cruises, restaurants, and hotels all over the world. As a result, the company had remote servers with attached storage, which was expensive to manage. In addition, the company grew concerned about the availability of the remote data. "I was not sure they were doing backups correctly or could recover," says Gary Johnson, Carlson's IT architectural consultant. The solution was to consolidate storage and backup at the central data center.

The company already had an FC storage array as its centralized storage and more FC out at its servers. Johnson used Cisco switches and IP to cross distances and Nishan to translate between IP and FC. "Using IP, I get scalability and reliability. I have a Fibre Channel SAN at the core and Fibre Channel SANs as islands of storage. Then, I route the traffic using IP," he explains. Carlson manages storage data traffic with its existing HP OverView management product as well as other standard IP traffic shaping tools. A private IP network--built around two Cisco 6509 Gigabit Ethernet switches and a set of Nishan FCIP storage switches--delivers the data with minimal latency and no dropped packets, Johnson says. In the future, the company intends to use iSCSI to ease the addition of new server hosts, enabling them to find the shortest path to the nearest Cisco switch by which they can access data stored on the FC disk arrays.

Ideally, Johnson would have liked to design Carlson's storage environment completely around IP, but the state of the technology when the company started in mid-2002--and even today--wouldn't allow a completely IP solution. "IP is a workable way to do storage, but you can't avoid Fibre Channel. You need to leverage it," he says.

This was first published in July 2003

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