One of the most basic types of instrumentation is adding logging statements to application code. In the past, these logs were saved to the disk of the server that ran the application. Retrieving and investigating these logs then took a lot of time and effort.

In modern hosting environments, logs are no longer saved on the local filesystem but instead stored remotely. With transient infrastructure and servers added or removed on the fly, it is no longer possible to store logs on the server and be sure that they can be retrieved later. For this reason, they are transmitted over HTTP to specialized log stores, such as Application Insights.