I'm running a pressflow site with over 40,000 unique visitors a day, and almost 80,000 records in node_revision, and my site hangs randomly giving 'site offline' message. I have moved my db to innodb and it still continues. I'm using my-huge.cnf as my mysql config. Please advice me on a better configuration and reasons for all this. I'm running on a dedicated server with more than 300GB and 4GB RAM.
The my-huge.cnf file was tuned for a "huge" server by standards of a decade ago, but it barely qualifies as a reasonable production configuration now. I would check other topics related to MySQL tuning and especially consider using a tool like Varnish to (since you're already on Pressflow) to cache anonymous traffic.