Explore the intricacies of managing large-scale information systems for security purposes in this conference talk from linux.conf.au 2020. Learn how to collect, process, save, and analyze vast amounts of data from thousands of devices using open-source tools like HAProxy, Logstash, Elasticsearch, and RabbitMQ. Gain insights from the University of Oslo's experience in processing billions of logs daily, and discover essential tips for building a resilient, high-availability system. Understand common pitfalls and lessons learned over four years of implementation. While no hands-on exercises are included, acquire the necessary background and theory to continue exploring this crucial aspect of infrastructure management independently.