Flash storage, fueled by dramatic price drops and density increases, is now a top contender for new enterprise storage applications. And not a moment too soon: the I/O randomization caused by widespread virtual machine adoption demands higher I/O performance. Faster than disks, cheaper than DRAM, flash is occupying a new layer in the storage pyramid.

Flash's low-latency, high IOPS, non-volatility and rapidly falling price make it a natural to replace costly enterprise disk drives. But should it be packaged as a disk drive? Disk interfaces add latency and reduce bandwidth. Flash performs best close to the CPU on a very fast bus. Flash can't be a replacement for DRAM: it isn't fast enough. But it can augment DRAM and improve system utilization and performance where its low latency and high bandwidth can be fully realized.