Monday, May 5, 2008

Hadoop at the heart of Yahoo Search

Hadoop running in production on the Yahoo! Search Webmap

"The Webmap build starts with every Web page crawled by Yahoo! and produces a database of all known Web pages and sites on the internet and a vast array of data about every page and site. This derived data feeds the Machine Learned Ranking algorithms at the heart of Yahoo! Search. Some Webmap size data:
- Number of links between pages in the index: roughly 1 trillion links
- Size of output: over 300 TB, compressed!
- Number of cores used to run a single Map-Reduce job: over 10,000
- Raw disk used in the production cluster: over 5 Petabytes"

Doug Cutting used to work at PARC, and we have been using Hadoop heavily in our research as well.

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