Micron's release of the P420m introduces a product that cuts through the cost barriers of PCIe SSD adoption. The advantages of flash, and primarily PCIe SSDs, are finally becoming crystal clear for the majority of users. The primary barrier remains the high acquisition cost of PCIe solutions, even when considering the massive long-term TCO advantage. The original PCIe SSD from Micron, the P320h, redefined the performance envelope for PCIe flash solutions. However, the use of high-cost SLC, though tremendously resilient to heavy workloads, relegates the P320h to upper-tier applications.
While the high-performance segment addressed by the P320h is large, the mainstream market is exponentially larger. Many might even argue that the P320h was the right solution for the market at the time, when many mainstream users were still wary of flash solutions. With its extreme endurance and high tolerance for heavy workloads, the P320h proved that bulletproof solutions for flash acceleration could gain significant penetration into the datacenter.
The flash market has matured considerably since then. The rate of adoption is staggering and at times the fabs cannot even produce NAND fast enough to satiate demand. If ever there were a time for a low cost solution that can deliver tremendous performance in a wide variety of use cases, the time is now.
The P420m looks to provide this low-cost MLC solution with higher capacities, yet also provide tremendous performance for the mainstream market. The common use-cases for the P420m run the gamut of mainstream applications from caching and OLTP to media streaming and web acceleration.
Micron leverages their vertical integration by utilizing their own 25nm NAND, DRAM, and Micron-developed application-specific integrated circuit (ASIC). The card comes in two form factors, the typical PCIe Gen2 x8 half-height half-length (HHHL), and a 2.5" form factor.
The slim profile of the HHHL P420m is designed for use in rackmount servers and is available in capacities of 700GB and 1.4TB. Both capacity points provide up to 3 GB/s of sequential read and up to 750,000 random read IOPS. The trade-off in the move to MLC is in write performance; the 700GB P420m offers 50,000 random write IOPS and 600 MB/s in sequential write. The 1.4TB unit provides 95,000 random write IOPS and 630 MB/s of sequential write speed.
The 2.5" P420m is the world's first PCIe Gen2 x8 MLC NAND PCIe SSD available in a SFF. These SSDs are hot pluggable and designed for utilization in the front bay of a server, thus reducing downtime and providing easy accessibility. The 2.5" comes in capacities of 350GB and 700GB, with sequential read performance up to 1.8 GB/s and random read performance topping out at 430,000 IOPS.
Endurance is always a concern in the datacenter, and is especially relevant with MLC solutions. To provide increased endurance, Micron implanted their XPERT (eXtended Performance and Enhanced Reliability Technologies) suite into a PCIe card for the first time with the P420m. This mix of technologies increases SSD performance and reliability, most notably through a RAID 5-like redundancy scheme (RAIN). We will cover this in detail in the following pages.
The XPERT suite provides an endurance of 5PB for the 700GB and 10PB for the 1.4TB, in stark contrast to the 50PB with the P320h. The lower endurance is enough for four drive fills per day for five years. The P420m also brings the inclusion of power hold-up capacitors as an additional layer of data protection in the event of power fail, a feature that was noticeably absent on the P320h.