By Dave Simpson
—Texas Memory Systems today announced a device that combines high-speed double data rate (DDR) solid-state disk (SSD) technology with lower-cost flash memory, a configuration that the company refers to as "cached flash." Volume shipments are expected in November.
The 4U RamSan-500 has 1TB or 2TB of flash memory that functions as primary storage, which is front-ended by 16GB to 64GB of DDR capacity that functions as a cache.
Texas Memory positions the RamSan-500 between high-performance, high-cost DDR SSDs and cached RAID systems.
The company claims performance specs of 100,000 I/Os per second (IOPS) of sustained reads, 10,000 IOPS of sustained random writes, and a read/write bandwidth of 2GBps. According to company officials, that is more than 16x the performance of some high-end hard disk arrays, yet the RamSan-500 consumes 50% less power (250 watts in the 2TB version vs. more than 500W for some RAID arrays).
Other performance claims include <200 microseconds for random read cache miss (from flash memory); <15 microseconds cache hit (read or write) from DDR; and <2 milliseconds write cache miss (from flash).
The SSD devices can be SAN-attached with two to eight 4Gbps Fibre Channel ports. (Support for 4x InfiniBand is expected in Q1 2008.)
The flash side of the RamSan-500 includes up to nine 256GB flash memory modules in a RAID-5 configuration. The system uses single level cell (SLC) technology. The DDR cache buffers I/Os, and the system optimizes write patterns to the flash media in the background.
But it's not cheap. A 1TB version is expected to sell for about $175,000, and a 2TB version for about $300,000.
The SSD market appears to be resurging, according to market estimates from International Data Corp. (IDC). For example Jeff Janukowicz, research director for SSD at IDC, say that current annual factory revenues are $77 million, and projected 2011 revenues are $1.26 billion—a compound annual growth rate of 75%.