white paper Introducing InSpeed Technology Breaking New Cost/Performance Barriers in Storage Networking

Transcription

1 white paper Introducing InSpeed Technology Breaking New Cost/Performance Barriers in Storage Networking by Thomas Hammond-Doel Director of Technical Marketing Vixel Corporation January 2002 real world solutions for storage networking AT VIXEL

2 InSpeed Fills A Need Expertise Creating New Technology... 3 An Economical Foundation... 3 InSpeed Technology Defined Reduces Complexity... 4 Robust, Economical Solutions... 4 True Switch Architecture... 4 No Latency and Transparent Operation... 4 InSpeed Implementations Storage Switch-On-A-Chip... 5 JBOD to SBOD Conversions... 5 Storage Switch Blades... 6 Vixel s Storage Switch Offerings... 6 InSpeed Applications Multiple Topologies... 6 RAID Applications... 6 InSpeed Performance Metrics... 7 Interconnect Price Factor... 8 InSpeed Performance Comparisons in a Real-World Setting Real Configurations... 8 Tuning Applications... 9 Conservative Numbers... 9 Real Performance Results... 9 Interoperability Affordable and Simple Storage Switching Benchmarks Powerful Solutions

3 InSpeed Fills A Need The world is becoming increasingly sensitive to complexity and cost. According to users who have deployed SANs, a high performance technology that significantly reduces the complexity and cost metrics while maintaining interoperability is not only demanded now, but is a requirement for growth in the Fibre Channel-based SAN marketplace. If this new technology provides the same performance as Fibre Channel fabric switching, the makings for a paradigm shift in the implementations of small to medium scale SANs are at hand. This innovative technology was invented by Vixel and exists today. It is called InSpeed technology. On the other hand, Gartner Dataquest believes the emergence of modular external hardware RAID controller-based storage systems that incorporate a fabric I/O infrastructure represents groundbreaking technology that will change the game in the competitive large-capacity enterprise storage market. Roger W. Cox Gartner Group Research Brief 11/01 Expertise Creating New Technology Vixel is a technology leader in Fibre Channel Fabric switching and the world leader in affordable SAN interconnect solutions. Many companies have tried to approach the problem of mitigating the cost and complexity of SANs, but have failed. The extensive experience Vixel brings to understanding affordable SAN deployments, as well as Vixel s patented technology, has led to a true breakthrough in storage switching and has eliminated the roadblocks encountered by other vendors. An Economical Foundation Vixel foresaw the pressing requirement and growing market demand for improving performance metrics such as input/output operations per second (IOPS) within NAS and RAID storage systems. As an outgrowth of these demands, Vixel developed InSpeed technology, a technology that has exceeded all expectations. The results are significant with measurable benefits that provide a compelling foundation upon which high performance storage architectures can be built. With this technology, an interesting side effect was created. Designed with high-performance minimum complexity and low cost, it was developed in order to meet the demanding requirements of embedded storage systems. However, due to its flexible nature, this same technology can be aimed at many previously unconsidered environments. In fact, with the use of InSpeed technology the user takes advantage of Fibre Channel based SAN connectivity for less than the price of IP solutions such as iscsi for small to medium scale SANs. 3

4 InSpeed Technology Defined Vixel s InSpeed is a brand new technology. InSpeed technology is an advanced switching architecture coupling a non-blocking crossbar switch with unique loop port logic resulting in a single chip capable of handling multiple Fibre Channel devices in embedded, blade and box environments. Actual implementations include embedded SERDES. Reduces Complexity Vixel s InSpeed technology, publicly introduced on July 30, 2001 ( pressroom/ html), features the highest performance, lowest cost interconnect architecture for 1 Gb/s and 2 Gb/s storage networks. It reduces the complexity and simplifies the deployment and management of SANs. InSpeed technology allows storage traffic to be switched at the arbitrated loop level, eliminating the need for attached devices to support complex, ever changing and ambiguous fabric services standards. IT personnel can now deploy SANs without a PhD in Fibre Channel standards and without the interoperability problems introduced by fabric services supported interconnect devices. Robust, Economical Solutions InSpeed technology advances the reach of Fibre Channel switch technology, allowing it to be embedded into environments that previously could not utilize switching technology. These areas include RAID, TAPE, NAS and next generation super-scalar storage systems. InSpeed technology is future-proofed by supporting both 1 Gb/s and 2 Gb/s Fibre Channel device speeds. Being the industries highest integrated Fibre Channel switch technology, Vixel InSpeed technology adds performance and system robustness that, for the first time, enables new levels of solution scaling and economics. True Switch Architecture InSpeed technology enables the next generation of simple and affordable storage switching by implementing a high performance non-blocking crossbar switch architecture. This is in contrast to traditional switch vendors use of the older, more error prone and non-scalable memory-mapped switching architecture. The resulting performance of an InSpeed-enabled ASIC often exceeds Fabric services switching speeds - at a fraction of the cost and complexity of a Fabric services based switch. No Latency and Transparent Operation During initialization, switches based on InSpeed connect all devices together in a standard FC- AL2 arbitrated loop using standards-based protocols. Upon receipt of the Fibre Channel primitive CLS at the end of the initialization process, InSpeed allows immediate transition to the switching mode. When arbitration is attempted, it analyzes connections and enables responses according to its current configuration. InSpeed operation is completely transparent to attached devices. In fact, attached devices require significantly less software to run in InSpeed environments than in fabric services based switching environments. This results in quicker initialization, less server CPU cycles and less management by the IT staff. There is no need for matching all the fabric services software revision levels or keeping up with all the ambiguous and incomplete ANSI fabric services standards. 4

5 InSpeed Implementations The following sections look at different uses of InSpeed technology. The general categories of implementation are in ASICs, blades and boxes. Storage Switch-On-A-Chip InSpeed technology provides storage switch-on-a-chip (ASIC) functionality for use in many different applications. The first such availability of this technology is inside the Vitesse VSC7192 ASIC. The VSC7192 can be used to turbo-charge RAID, TAPE, NAS and next generation super-scalar storage systems. The VSC7192 can operate as an unmanaged standalone device or can intelligently monitor, correct and report system status. The VSC7192 is available today and has been adopted by several end-user customers. JBOD to SBOD Conversions A powerful application of InSpeed Switch-On-A-Chip technology is to convert a JBOD (Just a Bunch of Disks) to an SBOD (Switched Bunch of Disks), as shown in Figure 1. SBODs used in applications accelerate performance and dramatically reduce FC-AL latency, as is shown in topologies 6, 7, and 8 of Table 1. Network Appliance, for example, will embed InSpeed technology into their JBODs to convert them into SBODs. This will effectively multiply the capabilities of their NAS solutions. Other vendors are implementing systems where InSpeed is deeply embedded into their system architectures, providing them with unprecedented performance. 0 1 Figure 1 JBOD vs. SBOD Architecture 2 JBOD Card or Backplane SBOD 6 7 InSpeed-based Card or Backplane 8 9 X -by-x Switch Matrix Topology # Table 1 IOPS & Price Performance Capabilities for RAIDS Interconnect Technology Target IOPS IOPS $ Factor 1 1 Gb/s* Loop 1Gb/s JBOD % 100% 2 1 Gb/s InSpeed 1Gb/s JBOD % 130% 3 1 Gb/s Fabric 1Gb/s JBOD % 540% 4 2 Gb/s InSpeed 1Gb/s JBOD % 140% 5 2 Gb/s Fabric 1Gb/s JBOD % 740% 6 2 Gb/s **Daisy Chain** 2Gb/s SBOD % 110% 7 2 Gb/s InSpeed 2Gb/s SBOD % 200% 8 2 Gb/s Fabric 2Gb/s SBOD % 800% * Reference Technology **Daisy Chain = No Interconnect Device 5

6 Storage Switch Blades Storage switch blades using InSpeed technology can be used to provide easy connection to RAIDs, or can be used to help consolidate multiple servers. Applications using storage switch blades range from aerospace to NEBS compliant telecommunications systems. Their versatility, low real-estate, stand-alone capabilities, and low power consumption make the use of InSpeed technology in storage switch blades ideal. The InSpeed-based controller card shown in Figure 1 on page 5 is an example of such a blade that is resident in a JBOD chassis and converting it into an SBOD. Vixel s Storage Switch Offerings Vixel s InSpeed enabled 2 Gb/s storage switches currently consist of 12-port, half-rack unmanaged storage switches, and 12-port, full-rack managed storage switches. These devices are currently being designed into the products of major OEMs for a multitude of uses. The results of these designs will increase performance by being embedded in enterprise level RAID and TAPE systems and will bring true affordable SANs to the small and medium scale IT shops. In addition, they will enable next generation super-scalar storage systems to offer scaling and performance never before offered or possible. InSpeed Applications Multiple Topologies Applications of InSpeed technology include embedding it into RAID, NAS, and TAPE storage systems, treed/daisy-chained JBODs or treed/daisy-chained SBODs, server and storage consolidation in small and medium scale SANs, and connection of storage segments to larger fabric infrastructures. RAID Applications There are two main categories of RAID architectures today: monolithic and modular. Examples of monolithic architectures are the EMC Symmetric, the IBM Shark and Hitachi Lightning. Examples of modular architectures are in products from Compaq, Dell, LSI, midrange IBM, and XIOtech. Monolithic RAID architectures take advantage of InSpeed technology in the following areas: Provide fan out from the host/san side connection to the RAID Provide connectivity between the front-end and backend modules Provide connectivity from the RAID controllers to the drives Provide drive isolation within attached JBOD cabinets to convert them into SBODs InSpeed technology is currently being designed into these types of architectures. Modular RAID architectures take advantage of InSpeed technology in the following areas: Provide connectivity between the RAID controller and the backend JBOD cabinets Provide drive isolation and switching within a JBOD cabinet to convert it into an SBOD Note that some mid to high-end NAS systems typically support Fibre Channel JBOD drives in the backend. These systems can utilize InSpeed technology in the same way a modular RAID controller can utilize it. 6

7 Finally, high-end tape libraries can also utilize InSpeed technology in the same way as a modular RAID controller, simply by substituting tape controllers in the place of JBOD drawers. InSpeed Performance Metrics The following data shows the enormous benefit of utilizing InSpeed technology in a modular RAID environment. Topology 1 in Figure 2 shows a reference topology using standard JBOD cabinets attached to dual RAID controllers. The topology allows for eight JBODs consisting of ten drives each, or 80 drives. The topology shown is greatly simplified, but is representative of a large number of implementations. The reference topology shown is one large arbitrated loop consuming 82 devices. In being conservative, this configuration can operate at 4000 IOPS, assuming single frame coalescing, 4K transfers, and a 50%/50% sequential read/write. Now change the reference (Topology 1 in Figure 2) by adding InSpeed into the JBOD to convert it into an SBOD or by adding an InSpeed-based storage switch between the RAID controller and backend JBOD. Both 1 and 2 Gb/s speeds are included (see topologies 2 8 in Figure 2). The base metric used in this review, IOPS, is generally increasing, with the various combinations, as shown in Table 1 on page 5. 1 Gb/s RAID 2 Gb/s RAID 1 Gb/s RAID 1 Gb/s JBOD 1 Gb/s JBOD 2 Gb/s RAID 2 Gb/s RAID 2 Gb/s JBOD 2 Gb/s JBOD 2 Gb/s RAID Figure 2 Reference Backend RAID Topologies 2 Gb/s SBOD 2 Gb/s SBOD 2 Gb/s RAID 2 Gb/s SBOD 2 Gb/s SBOD Topology 1 (Reference) Hub Topology 2 (1 Gb/s InSpeed) InSpeed-based Switch Topology 3 (1 Gb/s Fabric) Fabric Services Switch Topology 4 (2 Gb/s InSpeed) InSpeed-based Switch Topology 5 (2 Gb/s Fabric) Fabric Services Switch Topology 6 Daisy Chain SBOD Topology 7 (2 Gb/s InSpeed & SBOD) InSpeed-based Switch Topology 8 (2 Gb/s Fabric & SBOD) Fabric Services Switch 7

8 Interconnect Price Factor An interesting datum included in Table 1 on page 5 is the interconnect price factor. The effect of an estimated price of the interconnect, which consists of the concentrator and the JBOD/SBOD connection, is shown. Figure 3 graphically depicts the various HIGH COST LOW COST 1 Gb/s, Fabric, 1 Gb/s JBOD 1 Gb/s, Loop, 1 Gb/s JBOD 1 Gb/s, InSpeed, 1 Gb/s JBOD Figure 3 Price/Performance Topologies for RAIDs LOW PERFORMANCE 2 Gb/s, Fabric, 2 Gb/s JBOD 2 Gb/s, InSpeed, 2 Gb/s JBOD 2 Gb/s, Fabric, 2 Gb/s SBOD 2 Gb/s, Daisy Chain, 2 Gb/s SBOD 2 Gb/s, InSpeed, 2 Gb/s SBOD HIGH PERFORMANCE topologies against the price factor to clearly demonstrate how InSpeed technology drastically improves performance, but at only a fraction of the cost of a Fabric switch. InSpeed Performance Comparisons in a Real-World Setting The following highlights the high performance of InSpeed technology in real-world settings. This environment compares InSpeed with some traditional SAN interconnect solutions such as fabric switches, loop switches and hubs in a small to medium size SAN. The reference configuration uses pure FC-AL mode. All scenarios use the configuration in Figure 4. Real Configurations Table 2 shows the five different configurations for which data is presented. The Loop mode of the FC Switch is used as the reference. The private loop mode of the Vixel Gb/s Fabric switch is HBA #1 JBOD 1 HBA #2 HBA #3 Interconnect - Loop, Private Loop, Fabric Services or InSpeed-based Storage Switch JBOD 8 the mode in which an estimated 75% of all Fabric switches operate. The Fabric mode of the Vixel 9200 Fabric switch uses FL_Ports for all 12 connected ports. Table 2 Real-World Configurations Figure 4 Real-World Configuration Interconnect Technology Mode Bandwidth Hub Loop Shared 9200 Fabric Switch Private Loop Switching Switching 9200 Fabric Switch Fabric Switching InSpeed-based Storage Switch HBAs On Tree Ports Switching InSpeed-based Storage Switch HBAs On Device Ports Switching HBA #4 8

9 Tuning Applications The Tree and Device ports for the two InSpeed-based Storage Switches, shown in Table 2 on page 8, describe two of the three different modes in which the FC Switches may operate. These modes can be tuned to a particular application. Conservative Numbers Data comparing competitive Fabric switches to the Vixel 9200 has been collected, but that information will not be presented here. In all cases, the Vixel 9200 generally outperforms all competitors in real-world implementations of multiple servers and one or more RAID devices. The numbers presented showing the performance of the InSpeed-based devices is even better when compared to competitive products. Real Performance Results Figures 5, 6 and 7 show SCSI IOPS, MBps, and relative performance to arbitrated loop. The 50/50 Random Read/Write test case shows all devices performing about the same. This is due to performance of the system being disk-bound rather than interconnect-bound. IO TEST 50/50 Random R/W 256k 256k 6 6 Figure 5 IOPs Comparison Gb/s, 4 hosts (Emulex 950), 60 targets (Seagate 451), 6 enclosures, 4 outstanding IOs InSpeed Loop 9200 Loop 9200 Fabric InSpeed Tree InSpeed Device SCSI IOPs

10 50/50 Random R/W Figure 6 MBps Comparison Gb/s, 4 hosts (Emulex 950), 60 targets (Seagate 451), 6 enclosures, 4 outstanding IOs 256k TEST CONFIG 256k 6 6 InSpeed Loop 9200 Loop 9200 Fabric InSpeed Tree InSpeed Device MBps /50 Random R/W Figure 7 IOPs vs. Loop Performance Ratio Gb/s, 4 hosts (Emulex 950), 60 targets (Seagate 451), 6 enclosures, 4 outstanding IOs TEST CONFIG 256k 256k 6 6 InSpeed Loop 9200 Loop 9200 Fabric InSpeed Tree InSpeed Device Relative Performance 10

11 Two of the three write-only test cases show both private loop switching and fabric switching are faster than an InSpeed-enabled storage switch. This is due to buffers available with private loop and fabric services switches and the inherent slowness of hard drives when performing write operations. In all of the read-only tests, the InSpeed-enabled storage switch is faster than the private loop or fabric switches. In a real-world environment where the mixture of reads to writes distinctly favors reads, InSpeed-enabled storage switches are typically faster than private loop or fabric services switches. The relative performance chart (Figure 7 on page 10) shows that an InSpeed-enabled storage switch can be 600% faster than arbitrated loop depending on the topology and traffic. This relative performance is all at 2 Gb/s. When compared to 1 Gb/s, the results are almost twice that shown. It should be noted that although InSpeed performs faster than a traditional fabric services-based switch in real-world SAN deployments, it costs a fraction of the amount and is much less complex to deploy and manage than traditional fabric services-based switches. Interoperability As SANs have matured, interoperability issues have been slowly becoming less of an issue, but a SAN implementing fabric services has the largest set of outstanding issues. InSpeed technology does not participate in fabric services and is essentially transparent to the SAN. This means that SANs implemented with InSpeed technology do not have to implement complex and ever changing fabric services standards. Ease of integration because of no interoperability issues is a powerful benefit to the system architect and end user. This is another key point to emphasize. If a SAN implements fabric services, the level of special Fibre Channel IT expertise to manage the SAN becomes huge and the needed type of personnel are in short supply. On the other hand, a SAN without fabric services can be managed with current IT personnel with just a limited knowledge of Fibre Channel. This approaches the holy grail of SAN technology at IP network complexity and affordability. Affordable and Simple Storage Switching There is a distinct need for more affordable and less complex Fibre Channel SANs. This need is especially acute for small to medium scale IT deployments. Vixel s InSpeed technology is a new solution showing up in areas where traditional Fibre Channel interconnect technology is deemed too complex or too expensive. InSpeed-based deployments offer scalability, simplicity and performance at an exceptional value. Benchmarks When considering architectures that increase the IOPS especially when concerned with metrics such as the Transaction Processing Performance Council (TPPC - benchmarks InSpeed technology provides a viable and exciting alternative to competitive approaches. The TPPC routinely sees vendors struggle for the difference of a few percentage points in their system performance. The ability to multiply performance of SAN deployments be them RAID-based storage or NAS demands consideration. 11

12 Powerful Solutions Depending on the applications a vendor is deploying, the topologies provided in this paper clearly identify those areas where InSpeed can be used to add significant value. In particular, as the industry progresses more towards 2 Gb/s systems, a system using Vixel s InSpeed technology in conjunction with 2 Gb/s devices, will see increases over today s IOPS of hundreds of percent while adding only incremental cost to the overall solution. With the combination of minimal cost increases and accelerated performance vendors find they have more powerful solutions. Copyright 2002 Vixel Corporation. Contents Subject to Change. 12