Application performance management

In the fields of information technology and systems management, application performance management (APM) is the monitoring and management of the performance and availability of software applications. APM strives to detect and diagnose complex application performance problems to maintain an expected level of service. APM is "the translation of IT metrics into business meaning ([i.e.] value)."

Two sets of performance metrics are closely monitored. The first set of performance metrics defines the performance experienced by end-users of the application. One example of performance is average response times under peak load. The components of the set include load and response times:

The second set of performance metrics measures the computational resources used by the application for the load, indicating whether there is adequate capacity to support the load, as well as possible locations of a performance bottleneck. Measurement of these quantities establishes an empirical performance baseline for the application. The baseline can then be used to detect changes in performance. Changes in performance can be correlated with external events and subsequently used to predict future changes in application performance.

The use of APM is common for Web applications, which lends itself best to the more detailed monitoring techniques. In addition to measuring response time for a user, response times for components of a Web application can also be monitored to help pinpoint causes of delay. There also exist HTTP appliances that can decode transaction-specific response times at the Web server layer of the application.

In their APM Conceptual Framework, Gartner Research describes five dimensions of APM:

In 2016, Gartner Research has updated its definition, into three main functional dimensions:

Since the first half of 2013, APM has entered into a period of intense competition in technology and strategy with a multiplicity of vendors and viewpoints. This has caused an upheaval in the marketplace with vendors from unrelated backgrounds (including network monitoring, systems management, application instrumentation, and web performance monitoring) adopting messaging around APM^[which?]. As a result, the term APM has become diluted and has evolved into a concept for managing application performance across many diverse computing platforms, rather than a single market.^{[clarification needed]} With so many vendors to choose from, selecting one can be a challenge. It is important to evaluate each carefully to ensure its capabilities meet your needs.

Two challenges for implementing APM are (1) it can be difficult to instrument an application to monitor application performance, especially among components of an application, and (2) applications can be virtualized, which increases the variability of the measurements. To alleviate the first problem application service management (ASM) provides an application-centric approach, where business service performance visibility is a key objective. The second aspect present in distributed, virtual and cloud-based applications poses a unique challenge for application performance monitoring because most of the key system components are no longer hosted on a single machine. Each function is now likely to have been designed as an Internet service that runs on multiple virtualized systems. The applications themselves are very likely to be moving from one system to another to meet service-level objectives and deal with momentary outages.