Fibre Channel Coming Of Age

Adaptability is the key to survival. It's essential for evolved species of animals and especially for storage solutions providers. Storage is the place to be for VARs and systems integrators, mostly because all businesses and organizations need storage. Storage technology is still evolving. What about SCSI? What's going on with Fibre Channel?

Knowing how the storage market is evolving and keeping up with the changes is essential, according to Ken A. Marks, president of ANACAPA Micro Products, Inc. (Ventura, CA).

ANACAPA, a 30-employee, $25 million company, has undergone significant evolution since it was founded in 1991. Marks started it as a four-employee reseller of computer memory products. Then, ANACAPA started manufacturing its own memory line. As the market changed, the company began reselling storage products like disk and tape. Now, along with manufacturing memory and integrating storage solutions, it's entering the Fibre Channel domain.

When providing storage solutions, Marks knows that the long-range view has to be considered. "The long-range view used to be five years, but it's only 12 months now," he said. This is why VARs need to watch the changes in the market and be ready to adapt to them. And the dynamic technologies to watch now are SCSI and Fibre Channel.

SCSI Compared To Fibre Channel
SCSI was introduced in the 1980s, and it quickly became an industry-standard interface. It greatly improved communication between computers and peripherals like drives, printers, and scanners. Since it was first introduced, SCSI evolved nine times. From SCSI-1 all the way to Ultra3, also known as Ultra 160/m, SCSI technology doesn't seem like a nine-life cat ready to fall off the fence just yet. It's gotten faster, wider, and more ultra, but how does it compare with Fibre Channel?

The fastest SCSI can send data at 160 MB per second at maximum burst - great if you've been used to a data transfer speed of 40 MB per second. But Fibre Channel blasts away at 200 to 400 MB per second. Sounds like Fibre Channel is the way to go, right? Maybe so, but the SCSI Trade Association (STA) recently adopted a new technology road map planned to provide up to 640 MB per second. According to the STA, the new road map will increase manageability and offer more features for high-end desktop connectivity.

Currently, SCSI's speed is limited by its parallel nature. SCSI cables contain 68 individual wires that don't like to be run over long distances. Those wires are vulnerable to twists and turns that can occur over long connections between servers and peripherals. Fibre Channel cables are thinner and only contain four wires for a more stable, longer-length connection.

SCSI uses a shared bus cable with no hubs and prioritized arbitration. That can mean data log jams. Fibre Channel has multiple loops, hubs, and switches and allows equal arbitration. This means fewer bottlenecks. And, Fibre Channel frees up the LAN (local area network), while SCSI travels over it. Because of that, Fibre Channel allows non-disruptive addition and deletion of nodes (otherwise known as hot swappability). With SCSI, I/O (input/output) must be interrupted to add or delete nodes.

Fibre Channel devices, such as disk drives, usually have dual loops. This means if one loop fails, the device will still function without interruption. Parallel SCSI can only have 16 devices connected to it. Fibre Channel can handle 127 on a single loop. But, Fibre Channel only covers the physical aspects of connecting devices and transmitting data signals. It separates delivery from content. SCSI actually has two separate protocols. The lower level handles physical connections, while the upper level is a command message system for peripherals. And Fibre Channel is limited by existing SCSI equipment already installed. With fiber optic cable, it can be run over much longer distances than SCSI. When run along copper wire, however, the maximum distance covered becomes comparable to SCSI.

Where Should VARs Lead Their Customers?
"We're trying to lead our customers into Fibre Channel," said Webb Driver, ANACAPA's operations manager. "There's room to grow because of the expandability and the physical benefits. If a customer asks for RAID, we're there to offer a Fibre Channel RAID. But if the customer would rather stick with SCSI, we support that."

Driver doesn't think that SCSI will ever go away completely, at least not until far into the future. "Throughput is increasing in SCSI because of new developments, and SCSI is still making money for VARs and systems integrators," he said. "We aren't inventing Fibre Channel or SCSI. We add value by engineering hardware and software to complement the technology."

Many ANACAPA clients are involved in the graphics industry and software development. Marks said there's so much data that even a storage system installed two or three years ago must be updated. "It's really mandatory that VARs move into Fibre Channel to stay ahead of the competition. It's the next step in storage. You cannot avoid it if you're trying to have a position in the storage market."