Author: Rachelle Trent, SAS Product Marketing Manager,
PMC-Sierra

PMC-Sierra’s maxSAS™ storage family includes Serial Attached SCSI (SAS) expander switches with zoning support and intelligent Serial ATA (SATA) active/active multiplexers. It also includes SAS/SATA retimers and enclosure management processors supporting the 3.0 Gb/s SAS specification. To accelerate OEM and ODM development cycles for tiered-storage disk arrays, PMC-Sierra provides complete reference systems for its entire maxSAS product line.

PMC’s maxSAS products are all production released and shipping in volume, as follows:

PM8398 SXP 36x3GSec: 36-Port SAS Expander with Zoning
PM8399 SXP 24x3GSec: 24-Port SAS Expander with Zoning

The SXP 24/36x3GSec are the industry’s first zoning expanders compliant with the T10 SAS-2 specification for zoning. The SXP 24/36x3GSec provides zoning and security features that enable a new class of blade servers which provide substantial cost savings over current switching solutions (as shown in Figure 1). The SXP 24/36x3GSec offers increased system performance, high scalability and lower bill-of-material costs with an embedded MIPS-powered storage enclosure processor and complete Switch Management Software (SMS) for blade server equipment makers.

The SXP Reference Systems provide OEMs and ODMs with a fully functional SAS switch design that significantly reduces development costs and accelerates time-to-market. A key feature of the SMS is that it provides complete configuration and management of zoning across the entire SAS topology. In addition, the SMS displays, via a GUI, the SAS topology in a hierarchical fashion to facilitate the task of assigning the correct zoning attributes to expanders and end devices. The SXP 24/36x3G, combined with industry-standard SAS Controllers plus SAS and SATA HDDs, provides storage equipment manufacturers an end-to-end SAS and SATA storage systems solution.

Figure 1: SXP 24/36x3GSec Applications

PM8305 SPS 3G: SATA/SAS Active/Active Mux with NCQ
PM8307 SPS 3GT: SATA/SAS Active/Active Mux with NCQ

PMC provides two varieties of active/active muxes to encompass all applications requiring dual-port SATA HDDs.

The 4-port PM8305 SPS 3G is used for active backplanes that are required to support a mixture of SATA and SAS HDDs (as shown in Figure 2).

Figure 2: SPS 3G Active Backplane Application

The 3-port PM8307 SPS 3GT is typically used for SATA dual-port adapter cards, also called interposers or dongles as shown in Figure 3. These interposers (or dongles) are small printed circuit boards that interface to SATA HDDs. They enable the SATA HDDs to interface to SAS backplanes.

Figure 3: SPS 3GT Dongle/Interposer Application

The SPS 3G/3GT enables SATA HDDs to interface to SAS infrastructure while allowing system vendors to maintain their existing enterprise software architectures. The SPS 3G/3GT retimes the SAS HDDs high-speed links for increased reliability and provides advanced system-level features such as fault isolation and diagnostics to provide quick and accurate isolation of potential faults. The advanced diagnostics significantly reduce service times and unnecessary drive returns, resulting in substantial cost savings for storage system providers and information technology managers.

The key features of PMC-Sierra’s intelligent SPS active/active multiplexers include dual simultaneously-active ports, Native Command Queuing (NCQ) for high system performance, and an embedded microcontroller for advanced fault diagnosis and monitoring to reduce the number of working HDDs erroneously returned for servicing. It also includes HDD spin-down control for significant power savings and SATA Gen2x swing levels (1600 mV) for driving long backplane traces. Together with PMC-Sierra’s expander switches, the intelligent active/active SATA multiplexers form a complete SAS/SATA storage system solution.

Legacy SAS Products

In addition to the zoning expanders and active/active muxes, PMC has a wide cross-section of standard 3G SAS expanders ranging in size from six to 36 ports. PMC also has a four-channel SAS/SATA signal conditioner and mux device, called the QuadSMX. This device is used extensively in SAS and SATA systems to improve signal integrity (SI) on links that have poor SI performance.

For more Information on PMC-Sierra’s maxSAS product family, please visit: www.pmc-sierra.com/storage to find

• Product Datasheets
• Whitepapers on Storage Network Architectures and Design with High Speed Serial Technologies
• Webinars & Whitepapers on Designing SAS/SATA Storage Systems, SAS Topology Self Discovery and SAS Zoning