Switchtec PFX Application Use Case Series: Application of Switchtec in Scalable Storage Systems

Today’s data centers demand solutions that offer maximum performance, high reliability, and the lowest power consumption. Over the next few weeks, our blog series will showcase some of the best use cases for our industry-leading PCIe Switches, in design by our customers.

The Switchtec PFX PCIe Fanout Switch Family are PCIe Base Specification 3.1/4.0 compliant switches that support up to 100 lanes, 26 virtual switch partitions, 48 Non-Transparent Bridges (NTBs), and have hot- and surprise-plug controllers for each port. The PFX switches also feature advanced error containment and comprehensive diagnostics and debug capabilities. With superior flexibility, reliability, and power, cost, and board space savings, the Switchtec PFX PCIe Fanout Switches are a perfect fit for systems which are graded in terms of power costs, high-performance, and availability for failure-free uptime operation.

Typical applications for the PFX include data centers, defense and industrial servers, workstations, test equipment, video production and broadcasting equipment, cellular infrastructure, access networks, metro networks, and core networking. PFX switches are used in PCIe SSD enclosures, flash arrays, multi-host architectures, high-density servers, blade servers, and applications that require resilient PCIe switching.

Today, we want to discuss the application of PFX Fanout switches in scalable storage systems.

Use Case: Application of Switchtec PFX in Scalable Storage Systems

Many scalable storage designs implement a “scale-out” approach where storage capacity and performance throughput grow incrementally by adding more storage nodes to a networked system cluster. Each node can usually service client I/O requests, and each node may access any data in the cluster based on the way data is distributed and duplicated internally. Scalable storage systems are used in cloud storage, data-center and NAS/JBOF systems where there is a recurring need for higher storage capacity and storage nodes.

The Switchtec PFX switch connects to the Root Complex in the host system with a x8 or x16 upstream port (USP). The remaining PCIe lanes are configured as x4 or x2 downstream ports (DSP) to connect PCIe NVMe Solid State Drives (SSDs). Thus, a 96-lane Switchtec PCIe Gen3 PFX switch (PM8536) can support up to 20 x4 PCIe SSDs or 40 x2 PCIe SSDs on the remaining 80 lanes. Each port of the Switchtec PCIe switch supports a hot-plug controller, thus allowing the addition of a new SSD or the removal of failed SSD as needed while the system is in full operation. Assigning “USP with Management End-Point” in the switch partition or a Baseboard Management Controller (BMC) on the platform, helps to implement a Management Host which is required to support Intelligent Platform Management Interface (IPMI).

Figure 1. Single Host connectivity to SSDs using x2 and x4 bifurcation

The system may be scaled-out further by cascading two Switchtec PFX switches. Clocking mode, such as, Separate Reference Clock with Independent Spread Spectrum Clocking (SRIS) or Separate Reference Clock with No Spread Spectrum Clocking (SRNS) may be used in cascaded Switchtec PFX switch designs, to simplify clock routing between switches.

A Single host, multiple SSD configuration, provides high storage capacity, but it can also introduce a single point of failure on the single host. The host’s failure in the event of a system crash makes all SSDs inaccessible for the end-user. The solution to this problem will be discussed in the next Blog.

The application-specific configuration flexibility and interoperability with other PCIe devices, makes Switchtec PFX Fanout switches highly suitable for numerous applications in many different markets. Switchtec’s capability for further enhancement to support new PCIe capabilities and features using the built-in processor, helps its adaptation to use-cases, not foreseen during its development.

Next time, part 2 of our Switchtec PFX application use case series, will discuss application of Switchtec PFX in scalable storage systems with multiple hosts with multiple SSDs!

Product Availability

Microsemi’s Switchtec PFX PCIe Gen 3 Fanout Switch Family are in Production and available now. The Switchtec PFX PCIe Gen4 Fanout Switch Family, part of a complete end-to-end solution of infrastructure and endpoint solutions for PCIe Gen 4 applications, are sampling now to lead customers.

For details or to inquire about purchasing samples, please contact sales.support@microsemi.com or visit https://www.microsemi.com/product-directory/storage/4346-pcie-gen3-switches.

Please connect with me on LinkedIn to learn more or ask questions.

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