LENOVO 7N47A00097 - ThinkSystem HHHL PX04PMC 1.92TB Mainstream NVMe PCIe 3.0 x4 Flash Adapter

Lenovo PX04PMC. SSD capacity: 1.92 TB, SSD form factor: Half-Height/Half-Length (HH/HL), Component for: Server/workstation

Non-Volatile Memory Express (NVMe) is new PCIe 3.0 high performance solid-state storage technology that provides high I/O throughput and low latency. NVMe interfaces remove SAS/SATA bottlenecks and unleash all of the capabilities of contemporary NAND flash memory. Each Flash Storage Adapter has direct PCIe 3.0 x4 connection, which provides at least 2x more bandwidth and 2x less latency than SATA/SAS-based SSD solutions. NVMe Flash Storage Adapters are also optimized for heavy multi-threaded workloads by using internal parallelism and many other improvements, such as enlarged I/O queues.

The Lenovo NVMe Enterprise Mainstream Flash Adapters have the following features:

Half-high half-length PCIe adapter with PCIe 3.0 x4 host interface
Based on the Toshiba PX04P Add-in Card (AIC), PX04PMCxxx
19nm MLC NAND (128 Gb/die)
3 drive-write-per-day (DWPD) endurance for mixed read-write workloads
Full Power-Loss-Protection and End-to-End Data Protection
Low power consumption (maximum 18.5 W)

Enterprise Mainstream Flash Adapters and Enterprise Performance Flash Adapters have similar read IOPS performance, but the key difference between them is their endurance (or lifetime) (that is, how long they can perform write operations because Flash Adapters (like SSDs) have a finite number of program/erase (P/E) cycles). Enterprise Mainstream Flash Adapters have a better cost/IOPS ratio but lower endurance compared to Enterprise Performance Flash Adapters. Write endurance is typically measured by the number of program/erase (P/E) cycles that the adapter incurs over its lifetime, listed as the total bytes of written data (TBW) in the device specification.

The TBW value assigned to a Flash Adapter is the total bytes of written data (based on the number of P/E cycles) that an adapter can be guaranteed to complete (% of remaining P/E cycles = % of remaining TBW). Reaching this limit does not cause the adapter to immediately fail. It simply denotes the maximum number of writes that can be guaranteed. A Flash Adapter will not fail upon reaching the specified TBW. At some point based on manufacturing variance margin, after surpassing the TBW value, the adapter will reach the end-of-life point, at which the adapter will go into a read-only mode.

Because of such behavior by Enterprise Mainstream Flash Adapters, careful planning must be done to use them only in mixed read-write environments to ensure that the TBW of the adapter will not be exceeded before the required life expectancy.

For example, the 1.92TB NVMe Enterprise Mainstream Flash Adapter has an endurance of 10,412 TB of total bytes written (TBW). This means that for full operation over five years, write workload must be limited to no more than 5,705 GB of writes per day, which is equivalent to 3.0 full "drive" writes per day (DWPD). For the device to last three years, the write workload must be limited to no more than 9,509 GB of writes per day, which is equivalent to 5.0 full drive writes per day.