Metrics Glossary
This glossary is an exhaustive list of all metrics recorded by PM2 Plus. Understand what a metric stands for and how it is computed will avoid you to draw conclusions too quickly.
Note that each metric always describes the state of a specific application on a specific server. You may find some cross server metrics on the dashboard, to suggest on which application you could use the profiling for example, but in most cases, metrics are application and server specific.
CPU Usage
The CPU usage is the amount of time the CPU is busy. A CPU only can handle one operation at a time and so is either busy or idle.
Unit: %
Range of values: 0 - 100
Memory Usage
The memory usage is the total amount of memory used by the application.
Unit: Megabytes (MB)
Range of values: 0 - total memory of the server
Issues
The number of new issues recorded in the app.
Number of restart
The number of restart of your application since added to the PM2 process list. PM2 automatically restarts your application whenever needed, for example after an uncaught exception has happened.
Number of processes
The number of cluster on which your app has been spread on the server. Only PM2 clusters appear.
HTTP Requests per Minutes
Unit: Number of requests / minutes
Loop Delay
Unit: milliseconds (ms) Range: 0 - less than 100ms
The time the Node.js event loop takes to complete a loop.
Active Handles
Handles represent long-lived objects capable of performing certain operations while active. Some examples:
- A prepare handle gets its callback called once every loop iteration when active.
- A TCP server handle that gets its connection callback called every time there is a new connection.
Active Requests
Requests represent short-lived operations. These operations can be performed over a handle: write requests are used to write data on a handle; or standalone: getaddrinfo requests don’t need a handle they run directly on the loop.