What should you monitor?
The most crucial metric in MongoDB is memory usage. Like all database systems, MongoDB heavily relies on system memory to boost its performance. Whether you're utilizing the default WiredTiger storage engine configuration or not, it's essential to prioritize memory usage monitoring. Grasping the basics of how computer memory operates can give you an edge when interpreting metrics from your monitoring tools. Let's look at some fundamental concepts associated with computer memory.
Page fault
RAM provides speed but at a premium cost. In contrast, while hard disk drives (HDDs) and solid-state drives (SSDs) are slower, they are affordable and ensure your data remains intact during system or power hiccups. Typically, your data resides on these drives. When executing a query, MongoDB seeks the required data from memory. If it's not there, MongoDB retrieves it from the disk and transfers it to memory. This action is called a page fault since...
