12 Gb/s SAS flash manager delivers 300K IOPS

A 12 Gb/s SAS flash manager (SFM-12G) enables more than 320-K random read and 200-K random write IOPS at a write amplification of two (4-K block size) in a 2.5-in SAS SSD. The PM8304 from PMC integrates two ports of 12 Gb/s SAS-3, 16 channels of ONFI-2 and toggle-mode NAND flash channels, a DDR3 1600 x 40-bit controller, and two 900-MHz MIPS 34K CPUs, and multiple maxLIFE technologies. Its 5th-generation ECC algorithm offers sub-3-µs correction latencies.

The controller boasts a 16-µs cache memory hit latency, SLC cache memory miss latency of 47 µs, MLC cache memory miss latency of 72 µs, and throughput performance up to 2.4 GB/s. Statistics and flash monitoring capabilities include enhanced SMART statistics and monitoring; flash pool age, bad flash, and SCSI LU temperature reporting; and a robust set of event counters and statistics.

The management tool delivers intelligent, autonomous, configurable local page-level flash management, high performance write journaling, advanced flash reclamation and wear-leveling processes, and read and write cache with write coalescing and freeze/quiesce capability. It supports flash virtualization with up to 64 SCSI logical unit numbers, as well as write coalescing DDR cache, self managed local over-provisioning and wear-leveling, and host managed global thin-provisioning. Volume management capabilities include sparing, while flash management statistics enable optimized TCO.

The ECC capabilities include advanced line-rate HW to RBER=1 x 10-3 / UBER=1 x 10-16. The controller corrects up to 1644 bit errors per 4 KB page and maximizes NAND endurance and IOPS capabilities while minimizing impact on performance and utilized flash space over life of product.

12G SAS-3 ports feature:

• Two SAS 12/6 Gb/s narrow ports with unique world wide name
• Fully redundant dual-path-active-active target, active-active wide port target operation, and SAS active-passive modes
• SAS PHY, link, and SSP protocol layers
• Hardware termination and offload of SCSI SSP read/write commands
• Maintains IT Nexus context per operation
• 4.8 GB of aggregate bi-directional bandwidth
• Compliant with the SAS 3 specification

The PM8304 includes NAND flash interfaces with 16 channels, ONFI 2.x and toggle-mode support, up to 200 MT/s and 8 CE/lane, and up to 2 TB capacity. Configurable peripheral interfaces include eight parallel GPIO pins, serial peripheral interface (SPI) for firmware and VPD serial PROM, two multi-master two-wire interfaces (TWIs), and one industry-standard 16750 UART.

Caching features include:

• Read pre-fetch DDR cache memory
• Write coalescing and staging DDR cache memory
• Configurable RD/WR cache memory
• Optional cacheless operation
• SuperCap: Metadata flush and write-back DDR cache
• Without SuperCap: Write-through DDR cache and real-time metadata snapshot / journaling
• Four-way set associative, sectored cache memory per LUN

The PM8304 has a range of debug and diagnostic features like a UART Console for system monitoring and debug support, multi-thread EJTAG debug and RTOS visibility through Green Hills Multi IDE, device configuration via TWI, enterprise quality end-to-end data integrity, fault diagnostics and debug features (Debug, BIST and Loop Backs), and six-level error event response (correctable, recoverable, non-recoverable, critical, fatal, and catastrophic).

Availability:
PM8304 is sampling later this quarter. Visit the website for datasheets, pricing, and more.
 

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