Same here, have script running 24/7. 16gb data, Average table is 3 millions row, up to 64 million -
This sever is on vista 64, 8gb machine that doubles as my desktop.
Using latest beta versions of mysql for supposed better multi core support.
Heavily optimised mysql config and DB - still has some unavoidable slow queries, taking several seconds. But for us that's not a big problem as most time is spent crawling 100,000's urls a day.
More ram would and better performance would be nice - but then i'd run in to another bottleneck - cant hit some of these servers too hard so would have to build in a delay.
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Moved a site from a 4gb server to a 16gb server and lots of problems went away, but 100'sgb sounds mental