The Difference Between APM and Observability


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As software development shops have evolved, organizations have moved away from monolithic applications toward the development of more complex (and more resilient) distributed systems. With this evolution, application performance monitoring and system observability have become increasingly important. If you are new to the site reliability game, then you may be wondering why monitoring and observability have risen so much in priority. In addition – and reasonably so – you may be asking yourself: “what’s the difference?”

Below, I’ll explain the concepts of monitoring and observability as well as the difference between them. I will also discuss their roles in ensuring the reliability of modern applications and show you how intertwined they are in practice.

What Is APM?

APM, or Application Performance Management, refers to monitoring the performance and availability of an application. This is typically done using APM software like DX APM from Broadcom, a robust application performance monitoring solution that helps DevOps teams keep tabs on traditional application and system metrics (such as resource consumption, response times, and error rates) to ensure that the application is performing in a manner consistent with expectations.

By monitoring performance metrics over long periods of time, the process of determining typical and acceptable performance expectations for applications becomes much more straightforward for development and operations folks. Furthermore, a quality APM solution provides mechanisms for configuring alerts. Using historical performance as a baseline, you can configure alerts to notify the necessary personnel when performance metrics deviate too far from the norm (such as instances of severe or recurring latency, or higher than normal error rates). In this way, application performance monitoring provides instantaneous feedback regarding system failures.

What Is Observability?

Observability is defined as “a measure of how well internal states of a system can be inferred by knowledge of its external outputs. In the context of software, this would mean that a system is considered observable when no additional configuration is needed to increase visibility in order to determine the state of the system.

In many ways, observability goes hand in hand with APM. As mentioned above, application performance monitoring and performance management provide visibility into the performance of system components through the collection and analysis of traditional system metrics. From these metrics, you can create visualizations and derive insights that help determine the health of the system. In other words, these are the insights that help make the system observable.

In short, you can’t have observability without APM. Making a system observable is achieved in part through the implementation of a robust application performance monitoring strategy. And this strategy provides some of the crucial mechanisms by which the state of the system can be inferred.

The Role of APM and Observability in Site Reliability

Now that we have identified the (relatively subtle) difference between application performance monitoring and observability, let’s take a look at why they are so crucial for ensuring reliability in modern applications.

The Impact of Monitoring on Incident Response

At its core, site reliability is all about maximizing the amount of time that an application is available and meeting the performance objectives set by the organization. To succeed in this quest, several processes must be optimized. One such process is incident response.

A big part of an effective incident response process is the ability to recognize the occurrence and source of an application issue as soon as possible. Earlier, we mentioned that application performance monitoring enables increased visibility into system performance through visualizations and alert functionality that point the right personnel in the right direction to resolve an issue. Organizations that have effective incident management are able to leverage this visibility in order to reduce mean time to acknowledgement (MTTA) and mean time to resolution (MTTR) for incidents that threaten application performance, thereby decreasing their impact on end users while increasing overall performance on a consistent basis.

The Importance of Observability in Modern Systems

Modern systems are being built in a very different manner than those of years past. Today’s applications often feature a microservices-based architecture running across a distributed infrastructure. With so many moving parts and so many sources of information, it can be a much more complicated process to identify the source of a problem within the system. Therefore, when using modern development practices, it is critical to take steps to increase the observability of the application and its infrastructure.

Increased observability helps DevOps teams navigate the complexities that come with the increased fragmentation in distributed systems. To achieve this, organizations must implement processes that support thorough and effective application performance monitoring, distributed tracing, and effective log management. This ensures that development and operations folks have all they need when system stability is threatened due to incidents within an application’s features or supporting infrastructure.

In addition, increased observability helps provide insights into which areas need the most improvement. This insight helps determine where to focus developers’ efforts moving forward, thus ensuring that they are making the types of improvements that will have the greatest impact on the end users. Over time, this allows development teams to fine-tune application functionality in a manner that helps bolster application performance and reliability.


It’s easy to confuse observability with application performance monitoring, but there is a difference (however subtle it may seem).

APM is almost always accomplished with the help of software like Broadcom’s DX Application Performance Management tool. Application performance monitoring involves tracking system metrics and producing visualizations that are designed to provide DevOps teams with important data regarding system performance. This provides vital context for pinpointing the source of application issues as quickly and efficiently as possible.

Observability, on the other hand, is really more of an attribute than a process. A system is considered observable if its state can be easily determined without further implementations. In this light, APM represents a portion of the tooling and processes that are necessary to make a system observable. Therefore, while the concepts are different by definition, you can’t have observability without APM.

Scott Fitzpatrick has over 5 years of experience as a software developer. He has worked with many languages, including Java, ColdFusion, HTML/CSS, JavaScript and SQL. Scott is a regular contributor at Fixate IO.


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