Fusion's ioDrive dramatically improves application response times with a persistent,
http://www.fusionio.com/products/iodrive/
It's been used in severs for a few years now.
Unparalleled Performance Density
Fusion's ioDrive dramatically improves application response times with a persistent, high-performance, high-capacity ioMemory tier. It enables data decentralized architectures that move terabytes of process-critical data into servers. This minimizes application latency to deliver groundbreaking improvements to computing performance, while greatly reducing hardware infrastructure, maintenance, floor space, and energy costs. Minimizes latency and eliminates I/O bottlenecks by integrating with host servers as a memory tier extension.
Accelerating Your Data
Easily outperforms dozens of SSDs on a single server
Accelerates applications, improves response times, and boosts efficiency
Delivers the performance of thousands of disk drives in a single server
From 160GB - 640GB of enterprise solid-state flash
Easy installation and comprehensive data center management supported by the ioSphere Management Solution
Approved for enterprise use by Fusion-io partners, including HP, IBM, Dell, and Supermicro