Web search for a planet:: The Google cluster architecture

AMENABLE TO EXTENSIVE PARALLELIZATION, GOOGLE'S WEB SEARCH APPLICATION LETS DIFFERENT QUERIES RUN ON DIFFERENT PROCESSORS AND, BY PARTITIONING THE OVERALL INDEX, ALSO LETS A SINGLE QUERY USE MULTIPLE PROCESSORS. TO HANDLE THIS WORKLOAD, GOOGLE'S ARCHITECTURE FEATURES CLUSTERS OF MORE THAN 15,000 COMMODITY-CLASS PCs WITH FAULT-TOLERANT SOFTWARE. THIS ARCHITECTURE ACHIEVES SUPERIOR PERFORMANCE AT A FRACTION OF THE COST OF A SYSTEM BUILT FROM FEWER, BUT MORE EXPENSIVE, HIGH-END SERVERS.