MongoDB deploys to production environments with the intention of understanding how their applications will perform and minimize any potential surprises. To achieve this, it's essential to develop a consistent approach to managing the deployment environment, which includes prototyping, load testing, monitoring key metrics, and scaling accordingly. Proactive monitoring helps identify potential issues before they arise, such as memory usage spikes or write-lock fires. Several tools are available for monitoring, including MongoDB Management Service (MMS), nagios, munin, SNMP, mongostat, mongotop, iostat, and others. These tools provide insights into metrics like op counters, resident memory, working set size, queues, and lock percentage, allowing developers to optimize their deployment and ensure optimal performance. By closely monitoring these metrics during the testing period and in production, MongoDB deployments can be better prepared for heavy usage and potential issues.