Use FPGAs to harness potential of flash for enterprise apps

Enterprise storage subsystems nowadays are going through an essential transformation. The sheer volume of enterprise data and transactions is increasing by as much as 50-60% per year. The rapid proliferation of cloud computing and virtualization as a means to more efficiently manage these burgeoning data workloads has spawned explosive growth in the number and size of data centers. Along with the exponential growth in enterprise storage comes an imperative to improve memory subsystem performance capacity and value.

System administrators are finding that conventional storage architectures, which rely heavily on hard disk media, lack the performance to meet the demands of today's workloads. Application architects are responding by adopting a holistic approach to memory architecture that combines conventional storage media with a new entrant in the enterprise space, flash memory. Long a preferred memory medium for consumer devices, NAND flash memory offers 10-100X performance improvement over that of hard disk drives (HDDs) for enterprise applications. Flash is also the most cost-effective non-volatile storage medium for frequently used data and applications. By using flash memory arrays, enterprises can dramatically reduce storage footprint, CPU and software licenses, and consequently, data center power, space and operation cost.

At the core of this new high performance memory subsystem is a PLD-based Programmable State Machine (PSM). The PSM supports RAID algorithms (essential to ensure data integrity), memory control and high-speed I/O functionality. Programmable logic devices are particularly advantageous for these state machines owing to their inherent design flexibility, embedded processors, hardened memory controllers and high-speed serial I/O blocks. A flash memory architecture supported by a PLD-based PSM uniquely enables data center administrators to respond to the growing demands on their storage resources by balancing performance needs with data integrity, system scalability and serviceability.

Leveraging storage hierarchy
The various memory types and the role they play in a given storage subsystem can be viewed as a hierarchy, ordered in terms of performance, cost and capacity as illustrated in Figure 1. At the high end of the performance spectrum are embedded processor memory and L1/L2 cache. At the opposite end of the spectrum is tape back-up, which offers very high capacity storage at very low cost, but very slow speed. In between are the primary workhorses of storage subsystems: relatively fast and expensive DRAM, somewhat slower but less expensive and more capacious Flash RAM, and HDDs—traditionally the dominant storage medium in memory systems.