Problem

When you are configuring a Sentinel Server in Policy Studio, the screen shown below mentions an "overflow file." What is this file and where is it stored?

Resolution

The overflow file is a circular buffer file used by Sentinel that stores messages being processed by the embedded Universal Agent. It will always be of exactly the size configured in the Sentinel Server (default: 1 GB) and it does not grow or shrink during operation. When Axway Sentinel filters like Axway Sentinel Event are called, they store the message in this buffer file and return immediately. The actual message is sent asynchronously. Sending can fail, in which case the agent will continually retry, using the data stored in this file and erasing it once messages are sent.

One overflow file is stored in the instance directory of each instance configured to use Sentinel, for example, /apigateway/groups/group-X/instance-Y/[name].dat where [name] is the filename configured. The default name is text.dat.