A few weeks ago, Eran Hammer of Walmart labs came to the Node.js core team complaining of a memory leak he had been tracking down for months. By expending a lot of effort over those few months he had taken the memory leak from a couple hundred megabytes a day, down to a mere eight megabytes a day. That in and of itself is an impressive feat, however, the source and final portion of the leak was elusive.
More info: http://www.joyent.com/blog/walmart-node-js-memory-leak
More info: http://www.joyent.com/blog/walmart-node-js-memory-leak