minimize the server work; get some cheap nodes at rackspace cloud; use one node for sessions in memcache; use two nodes for mongodb (master/slave) read from bo

minimize the server work; get some cheap nodes at rackspace cloud; use one node for sessions in memcache; use two nodes for mongodb (master/slave) read from both; try to minimize xss/html/js and gzip everything; cache as much as possible; maybe even queue inserts/updates with redis and a cron; thats how i survived a mini fb app thatwent from zero to 44 million users in 7 days... rackspace cloud + memcache + redis insert&update queue + round robin. after a month i even killed the rackspace cloud interface and api with over 80 nodes and growing. had to get the memory limit on my account raised twice. peak were around 40k req/sec. after the second month we moved it to four bulky servers (16 core, raid5, 32gb ram) each cost around 12k dollar. the whole secret is caching. everything, everywhere and as much as possible.