HBA vendors tackle next-generation SANs

Posted on June 01, 1999


HBA vendors tackle next-generation SANs

Fibre Channel host bus adapters are an integral part of OEM system and enterprise SAN capabilities.

By John Haystead

No longer just an enabler for specialized applications, Fibre Channel has captured the attention of a long list of OEMs. As the technology enters mainstream architectures, Fibre Channel developers are no longer targeting niche products and applications, but are catering to the demands of OEM customers with adapters that can be easily integrated into complex server and storage systems.

This development is evident in the improved performance, scalability, and sophistication of new Fibre Channel host bus adapters (HBAs), as is the focus of developers on meeting the increasingly demanding requirements of next-generation storage network architectures.

The primary driver behind rapid growth in the Fibre Channel market is its close connection to the implementation of storage area networks (SANs). As observed by Samir Desai, product manager for Fibre Channel products at QLogic, "SAN market growth is a direct function of the solutions available, and it is Fibre Channel that has enabled SANs." Therefore, with the emergence of host SAN systems comes a concurrent watershed in the adoption of Fibre Channel technology and HBAs.

Mike Smith, senior director of Fibre Channel marketing at Emulex, major OEMs have evolved through the selection, development, and integration phases and are now in deployment, launching systems in volume." Walt Krysiak, product marketing manager at LSI Logic, echoes this observation: "This year and next will clearly be the time frame of the `hockey stick` effect for Fibre Channel, where the market really takes off."

Fibre Channel is attracting renewed attention from existing Fibre Channel product providers. For example, Hewlett-Packard`s Components Group, an early provider of Fibre Channel protocol controller ICs with its Tachyon device family is expanding its presence in the market with HBA`s as well. As described by Mike Dreitlein, program manager for HP`s Fibre Channel Solutions, "Though we`ve invested in Fibre Channel for some time, the market is just now at the takeoff point, and OEMs are looking for the capabilities and flexibility Fibre Channel provides to SAN implementations."

As server and storage system OEMs embrace Fibre Channel, they`re also gaining much more control over the direction and design of core technology and products. For example, since each server and storage subsystem provider individually qualifies the HBAs they plan to incorporate into their products, vendors are understandably eager to provide OEMs with specific capabilities and features they want to differentiate their system-level products.

One immediate benefit of this close relationship is improved compatibility and interoperability at the HBA level. "OEMs do extensive testing not only of components but complete solutions, and it`s not uncommon for an OEM to flag something that we haven`t seen before because of the unique way they are deploying a system," says Emulex`s Smith. "We can react with a modification to our firmware or drivers to support specific configurations."

LSI`s Krysiak agrees: "OEMs are helping to rapidly address interoperability issues and build up the Fibre Channel infrastructure. There are still some interoperability issues preventing plug-and-play operation, but industry initiatives are underway to resolve these as well."

On the other hand, since OEMs are offering complete solutions, inter-system integration issues don`t always get the same level of attention. As pointed out by Rick Franz, QLogic`s director of corporate marketing, "Our OEM customers have a defined set of parameters and configurations that they plan to ship. As a result, their overriding interest is whether our HBAs will work with the specific switches, hubs, and software they`ve selected for these solutions. Interoperability with other devices is often a secondary issue."

A related result may be a lag in the appearance of heterogeneous SANs. Says HP`s Dreitlein, "Right now, Fibre Channel is being sold to OEMs for deployment in homogeneous system environments. The channel isn`t yet at the stage where you`ll see heterogeneous systems with multiple server platforms and switches on the same SAN, although that will eventually develop."

Looking further down the road, other interoperability obstacles must also be overcome before open-architecture solutions are possible. "Although we`ve pretty much licked interoperability at the HBA level, that doesn`t mean you can build heterogeneous SANs," says HP`s Dreitlein. For example, switch interoperability remains a particular concern. Here, most observers agree that a major industry force will need to intercede and institute a de facto standard before the current problems with inter-switch communications can be resolved.

Nevertheless, QLogic`s Franz notes that interoperability issues are continually being addressed, and in the meantime end-to-end solutions are being delivered. "True, the solutions will be very server-centric, as they are today with SCSI, but as more products are integrated by OEMs, it will be a lot easier for other system integrators to come on board and fairly seamlessly plug this stuff together and deploy it," says Franz.

Furthermore, as observed by Mark Friedmann, president and CEO of Prisa Networks, the move toward more complex SAN implementations may actually provide an HBA interoperability benefit, at least in the short term. This is because of a move away from loops to switched fabrics.

HBA interoperability is more of an issue on loops than on switched fabrics. Notes Friedmann, "Devices still need to service both environments, but there`s more intimate interaction required between HBAs from different vendors sharing the same loop than on a switched fabric where all they really have to do is log into a particular switch."

"From the start, Fibre Channel has been an extremely flexible protocol, allowing HBA vendors to implement, or choose not to implement, a mix of options in their products," says Emulex`s Smith. While beneficial in some ways, it has also led to a wide variety of HBA products tailored to specific requirements, environments, and cost points. For example, some vendors have chosen to support Fibre Channel Arbitrated Loop (FC-AL) exclusively, ignoring Fibre Channel`s switched-fabric capabilities, while others have chosen to support only Class III service and not Classes I and II.

While these variations were viable in the early stages of Fibre Channel`s development, existing users may find their HBAs to be lacking as they move up to more complex implementations. "As users transition from simple loops to switched fabrics and complex SANs, they may discover their HBAs don`t have all the features they need," says Smith.

Performance issues

Performance is perhaps the most fundamental parameter for a Fibre Channel HBA. However, as pointed out by Dan Bochsler, Fibre Channel business line manager at Interphase Corp., raw performance specs don`t tell the whole story. "The same fallacy is often adopted in measuring Fibre Channel HBA performance as was the case when it was assumed that the highest MHz CPU was the best solution in all cases. In fact, true performance is ultimately driven by the application environment."

Fibre Channel applications tend to fall into two basic categories: database or transaction environments where the number of I/O operations per second are maximized, and pure throughput environments such as video editing and video-on-demand, which are best measured with a MBps yardstick. "Without putting together a heterogeneous system, it`s not possible today to fully address both of these environments in a single system configuration," says Bochsler.

Prisa Networks is one HBA supplier primarily concentrating on digital media SANs. "Our users are looking for throughput, as opposed to I/Os per second," says Friedmann, "and as such we optimize the design of our boards for high-speed data streaming with such things as larger FIFO buffers and specialized algorithms for pre-fetching data with fewer memory accesses." With ever-increasing demand for shared file systems among a large base of implementers, heterogeneity and compatibility remain key requirements for SANs in video applications, add Friedmann.

The Fibre Channel market has clearly broadened, however, from its early, almost exclusive, focus on video applications. And as Fibre Channel is deployed in more mainstream enterprise applications, system up-time and reliability must be added to the list of critical HBA characteristics. Emulex`s Smith points to a number of specific HBA features that address these reliability concerns. For example, "we believe the Class II protocol is a more reliable mechanism for delivering data and an important attribute for HBAs in the enterprise space." End-to-end parity, built-in-test, logic scan, and accelerated stress testing also increase reliability.

HBA scalability is, of course, a particularly crucial parameter for high-end enterprise applications, particularly as the industry moves to multi-processor and cluster environments. As noted by QLogic`s Desai, "The more adapters users can attach to their servers, the more storage they can access, and the more processing power they can bring to bear."

Raw performance is also important in these environments. Interphase`s Bochsler points out: "Here, you`re looking for close to linear scalability in performance and throughput, and you have to ensure that the data-flow connection points in your HBA maximize the capabilities of multi-processor systems and don`t top out at some point as you add adapters."

QLogic`s Desai adds another observation on the performance issue: "It`s not just raw I/O performance, but the amount of CPU horsepower the adapter uses up to achieve that performance level."

IP support

One trend expected to have an increasing impact on HBA product design is the growing demand for multi-protocol support, particularly for IP. Driven by the Web, IP networks continue to prolifer-ate with a concurrent push to digitize information, often requiring enterprises to double their storage capacity on an annual basis.

According to Emulex`s Smith, "While, up to this point, most Fibre Channel users have focused exclusively on moving storage data, we`re now getting a lot more requests to support concurrent SCSI and IP." One goal is to allow users to perform in-band management of both the SAN and CPU clusters. Interphase`s Bochsler sees the same phenomenon: "Virtually 100% of our customer base is now demanding high-performance TCP/IP support in addition to SCSI."

However, concurrent IP support introduces new requirements for measuring HBA performance. "Where you can often approach Fibre Channel`s theoretical MBps throughput max in SCSI I/O operations, the comparison scale with TCP/IP on Fibre Channel is instead the typical throughput of other media such as Fast Ethernet, which typically delivers on the order of 10MBps or 100Mbit-per-second traffic," describes Bochsler.

Ultimately, says Bochsler, "the true promise of Fibre Channel will be realized when it`s viewed more as a generic transfer medium than a specific protocol." High-performance, scalable, and flexible HBA products will clearly play a big role in achieving this goal, but in the meantime, users need to make sure that the HBAs incorporated in the OEM systems that they`re buying and implementing today will allow for future growth and SAN complexity.

Racing ahead to 64-bit/66MHz PCI

PCI bus throughput and conversion speed is clearly one of the rabbits in the dog race to provide the fastest Fibre Channel host bus adapters (HBAs). In anticipation of the ever-increasing demands expected for network storage systems, Fibre Channel HBA vendors are leapfrogging their products` capabilities ahead of the bulk of deployed PCI systems with 66MHz/64-bit products.

QLogic is first in production with a Fibre Channel-to-66MHz PCI chipset and associated HBAs. Rick Franz, director of corporate marketing, says that while there are only a few server companies currently offering 66MHz PCI, the capability will become increasingly important. "In the second half of this year, we expect to see just about everyone offering 66MHz PCI slots."

QLogic`s QLA2100F/66 64-bit/66MHz offering supports 100MBps Fibre Channel data transfer rates and PCI bus master data transfers of up to 528MBps. A message-style host software interface allows the board to operate independently of the host system with "nearly complete" host software compatibility between parallel SCSI and Fibre Channel applications.

Hewlett Packard`s Components Group has also announced production of its 32/64-bit HHBA-5121A, a 66MHz PCI-Fibre Channel HBA based on the latest version of the Tachyon TS protocol controller IC (see InfoStor, April, p. 1). Mike Dreitlein, program manager for HP`s Fibre Channel Solutions, points out that 66MHz/64-bit PCI will be an increasingly common requirement for future I/O subsystems in order to keep pace with the bandwidth of multiple Fibre Channel channels or combinations of Fibre Channel and Gigabit Ethernet.

HP`s HBA is compliant with FC-AL-2 and includes support of PCI dual address cycles, FC-AL Class 3 service, including public loop and fabric (F- and FL-port login), and full duplex operation with parallel inbound and outbound processing. The adapter also features a "hub-on-a-board" feature where port-bypass circuits allow multiple internal and external connection configurations.

LSI Logic has also announced a pair of 64-bit/66MHz PCI boards based on its SYMFibre Channel909 protocol controller. Targetting SAN and server-clustering environments, both HBAs incorporate LSI`s "SAN Engine" technology. The SYMFibre Channel909 model has an HSSDC connector for copper connections, while the SYM40909G supports the GBIC interface module for both optical and copper interfaces.

According to Walt Krysiak, product marketing manager, the devices will deliver full-duplex speeds up to 200MBps and support Fibre Channel Classes 2 and 3 as well as both Fibre ChannelP SCSI and IP. Krysiak also points to a "link-check" software utility feature that will allow users to perform a type of bit-error-rate check on the link. Samples are due in the third quarter, with production quantities by year-end.

JNI leverages Adaptec technology

Next month, JNI plans to begin volume shipments of two 33MHz PCI-to-Fibre Channel host bus adapter cards--the 32-bit FibreStar FCE-3210 and 64-bit FCE-6410. The HBAs are the result of JNI acquiring Fibre Channel intellectual property and assets from Adaptec earlier this year. Both adapters are based on the Emerald III chip architecture, which JNI eventually plans to use in its HBAs for Sun Sbus platforms. (The Sun HBAs are currently based on HP`s Tachyon chip.) The HBAs support Class 2 and 3, as well as all Fibre Channel topologies (point-to-point, switched fabric and arbitrated loop).

JNI hopes to differentiate its HBAs with the bundled EZ Fibre software, a Windows NT-based configuration and management utility for easier, GUI-based diagnostics and SAN installation. Scott Ruple, vice president of marketing at JNI, says that incorrect configuration of host bus adapter cards is the primary reason for most SAN failures. EZ Fibre software also provides LUN-level zoning for heterogeneous host environments.

The FCE-3210 is list priced at $745 with copper connectors. The FCE-6410 starts at $895 with copper connectors, and ranges up to $1,095 with full buffering and optical connectors.

Separately, JNI has demonstrated a 2Gbps Fibre Channel HBA with full-duplex 400MBps throughput. Small quantities of the card began shipping this month to developers.

Click here to enlarge image

JNI`s PCI-to-Fibre Channel host bus adapters are based on the AIC-1160/JNIC-1160 Fibre Channel controller and Serializer/Deserializer (SERDES) chipset.

John Haystead is a freelance writer in Bucksport, ME, and a frequent contributor to InfoStor.

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