Summary
Using Elgg in a production environment involves a wide range of skills. There is selection and configuration of the server. The Elgg application and its users require administrative attention. Backups must be made in case anything goes wrong with the server. There is also performance tuning and upgrade planning to handle growth. The amount of time and effort required depends on factors such as the criticality of the site and its growth. If a growing user base is causing you to spend time with the MySQL manual (or hire someone to tune your server), then it is a good problem to have.