All of this adds up to a greater adoption of monitoring tools and services. As much as we can script some of them, integrating with cloud and on-premise monitoring tools can help us to achieve more in a smaller amount of time.

The metrics that we keep a track of should do one of the following:

• Detect failures: Failure detection is a reactive process, where we should have clear protocols in place for what happens when each of the failure detection flags goes off. For example, what should the recovery steps be if we lose a server, a replica set, or a shard?
• Prevent failures: Failure prevention, on the other hand, is a proactive process, designed to help us catch problems before they become a potential source of failure in the future. For example, CPU/storage/memory usage should be actively monitored with yellow and red thresholds, and clear processes should be put in place as to what we should do in the event that we reach either threshold.