Cheap and Large CAMs for High Performance Data-Intensive Networked Systems

Date Added: Mar 2010
Format: PDF

The authors show how to build cheap and large CAMs, or CLAMs, using a combination of DRAM and flash memory. These are targeted at emerging data-intensive networked systems that require massive hash tables running into a hundred GB or more, with items being inserted, updated and looked up at a rapid rate. For such systems, using DRAM to maintain hash tables is quite expensive, while on-disk approaches are too slow. In contrast, CLAMs cost nearly the same as using existing on-disk approaches but offer orders of magnitude better performance. The design leverages an efficient flash-oriented data-structure called BufferHash that significantly lowers the amortized cost of random hash insertions and updates on flash. BufferHash also supports flexible CLAM eviction policies.