HashCache: Cache Storage for the Next Billion

We present HashCache, a configurable cache storage engine designed to meet the needs of cache storage in the developing world. With the advent of cheap commodity laptops geared for mass deployments, developing regions are poised to become major users of the Internet, and given the high cost of bandwidth in these parts of the world, they stand to gain significantly from network caching. However, current Web proxies are incapable of providing large storage capacities while using small resource footprints, a requirement for the integrated multi-purpose servers needed to effectively support developing-world deployments. HashCache presents a radical departure from the conventional wisdom in network cache design, and uses 6 to 20 times less memory than current techniques while still providing comparable or better performance. As such, HashCache can be deployed in configurations not attainable with current approaches, such as having multiple terabytes of external storage cache attached to low-powered machines. HashCache has been successfully deployed in two locations in Africa, and further deployments are in progress.