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

We 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. Our 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. We prototype CLAMs using SSDs from two different vendors. We find that they can offer average insert and lookup latencies of 0.006ms and 0.06ms (for a 40% lookup success rate), respectively. We show that using our CLAM prototype s...

• Type: Conference
• Year: 2010
• Where: NSDI
• Authors: Ashok Anand, Chitra Muthukrishnan, Steven Kappes, Aditya Akella, Suman Nath
• Keywords: Clam, Computer Networks, Hash Tables, NSDI 2010, On-disk Approaches