Maximum SAS Performance with PMC-Sierra’s maxSAS Product Family

Author: Rachelle Trent, SAS Product Marketing Manager

PMC-Sierra’s maxSAS™ storage family includes Serial Attached SCSI (SAS) expanders, SAS/Serial ATA (SATA) retimers, SAS/SATA multiplexers and enclosure management processors. To accelerate OEM and ODM development cycles for tiered storage disk arrays, PMC-Sierra provides complete reference systems for its entire maxSAS product line.

The latest editions to PMC’s maxSAS family include SAS expander switches with zoning support and intelligent SATA active/active multiplexers. A complete SAS/SATA storage system solution can be realized by using PMC’s SAS expander switches combined with the intelligent active/active SATA multiplexers.

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 that are compliant with the ANSI INCITS T10 SAS-2 zoning proposal. The SXP 24/36x3GSec provides zoning and security features that enable a new class of blade servers based on end-to-end SAS electronics, providing substantial cost savings over current switching solutions (as shown in Figure 1). The SXP 24/36x3GSec offers increased system performance, higher capacity, scalability and lower bill-of-material costs with an embedded MIPS-powered storage enclosure processor and complete reference system, together with Switch Management Software (SMS) for blade server equipment makers.

The reference system provides 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 access control zones 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, SATA multiplexers and SAS and SATA hard disk drives (HDDs), provide storage equipment manufacturers with an end-to-end SAS and SATA storage systems solution.


Figure 1: SXP 24/36x3G/Sec Applications


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

The four-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). The three-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 PCBs that interface to SATA HDDs. They enable the SATA HDDs to interface to SAS backplanes. The SPS 3G/3GT enables SATA HDDs to interface to SAS infrastructure while allowing system vendors to maintain their existing enterprise software architectures. It retimes the SAS HDDs high-speed links for increased reliability. In addition, the SPS 3G/3GT provides advanced system-level features such as fault isolation and diagnostics that allow quick and accurate isolation of potential faults. This significantly reduces service times and unnecessary drive returns to result in substantial cost savings for storage system providers and information technology managers.

The key features of PMC-Sierra’s intelligent SPS active/active multiplexer include dual simultaneously active ports, Native Command Queuing (NCQ) for high system performance, an embedded microcontroller for advanced fault diagnosis and monitoring to reduce the number of working HDDs erroneously returned for servicing, 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.


Figure 2: SPS 3G Active Backplane Application


Figure 3: SPS 3GT Dongle/Interposer Application


For more Information on PMC-Sierra’s maxSAS Product Family including;

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

Please visit:

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.