Caching in on Memcached
As its name implies, the Schooner Appliance for Memcached is built to run Memcached, a key/value distributed cache commonly used in high-traffic Web sites. According to Busch, legacy Memcached installations are typically limited by the amount of DRAM that can be installed in a single server node. An application that requires a total of 512GB of memory is typically spread across 16 Memcached server nodes at 32GB of DRAM per node. Further, most legacy Memcached nodes use only 1Gb Ethernet links, which are sufficient because of the limited amount of DRAM and CPU throughput per node, according to Busch.
The Schooner Appliance for Memcached, by comparison, is capable of balancing 16-core hyperthreaded Nehalem processing with the network bandwidth of multiple 1Gb or 10Gb Ethernet links, and hundreds of thousands of accesses per second of flash memory.
It boils down to this: One appliance is able to handle 512GB of cached data. Thus, handling a 1TB Memcached workload would require four 2U Schooner appliances drawing 2.5kw, compared to 33 2U legacy servers, which would consume around 18.7kW. That represents a 50 percent reduction in operating costs over three years, according to Schooner, while reclaiming a significant amount of floor space.
The Schooner appliances won't officially ship until early next year, though a handful of undisclosed companies have been beta testing them. Given the backing that the technology is receiving from IBM, I believe it's a product offering well worth watching, as it addresses a critical challenge in the Web 2.0 datacenter. Costly, wasteful server sprawl and underutilization won't end overnight, but purpose-built appliances like this are going to help significantly.