Solid-state drives (SSDs) use solid-state NAND flash memory to store data rather than the rotating magnetic recording media of hard disk drives (HDDs). Even the latest HDDs can be performance limited by the spindle speed of the disk (15K rpm). Solid-state technology has no moving parts and does not suffer from the mechanical constraints of HDDs. Nonvolatile NAND flash replace mechanical drives in solid-state storage solutions, designed to provide fast, reliable, low-power and cost-effective storage devices. Two NAND types are in use today:
SAS/SATA SSDs are similar to HDDs in that they use the same interface and, therefore, are accessed by the system through the same OS driver stack. While SAS/SATA solid-state storage devices offer significantly better performance over standard rotating media HDDs, their performance can be limited by the latency and bottlenecks inherent in the driver stack. A single Express Flash drive can achieve up to 10.5x more database transactions per second than HDD storage.
A PCIe solid-state storage solution (SSS), on the other hand, is directly connected to the PCIe bus. The PCIe bus provides a direct connection between the PCIe-SSS and the CPU as well as system memory. This tightly coupled connection can deliver a storage environment that has lower latency than a SAS/SATA SSD.
Dell™ PowerEdge™ Express Flash PCIe-SSD
The PowerEdge Express Flash PCIe-SSD is a high-performance storage device built with enterprise-class SLC NAND flash designed for solutions requiring low latency, high I/O (input/output) operations per second (IOPS), and enterprise-class storage reliability and serviceability. The Express Flash PCIe-SSD is a PCIe Gen2-compliant device and can be configured as storage cache or as a primary storage device in demanding enterprise environments, such as enterprise blade and rack servers, video-on-demand servers, web accelerators and virtualization appliances. A single Express Flash drive response time can result in up to 26 ms, up to 1/4th lower than 4 SAS SSD drives and up to 1/10th the latency of 16 traditional HDDs.