Let me just caution those with highly scalable expectations. A large MongoDB instance is going to weight in at around 1-10TB. Here's an updated list of produc

Let me just caution those with highly scalable expectations. A large MongoDB instance is going to weight in at around 1-10TB. Here's an updated list of production MongoDB instances for reference: http://www.mongodb.org/display/DOCS/Production+Deployments http://www.mongodb.org/display/DOCS/Production+Deployments At both Splunk and Loggly I've seen customers sending in multi-tens-of-millions events a day from a handful of boxes without even breaking a sweat. It wouldn't take long to blow through several TB of storage in MongoDB if you were storing all that log data with a retention of a few months. Log volumes vary from use-case to use-case though, and I absolutely love the GrayLog2 guys and the way they listen to their users. It's definitely a great tool for a job that is usually a real pain in the ass!