Openfire uses an embedded Jetty web server (version 9.2.14 at the time of writing). In its operation, Jetty places some files in the designated 'tmp' folder of the operating system. Expanded war files appear to go here, for example.
Some operating systems periodically purge their 'tmp' folder, which can remove the files needed by Jetty.
We've observed that an Openfire Meetings instance becomes unreachable after 10 days on a specific Amazon AMI based server (which used tmpwatch to remove files after 10 days of inactivity).
A way should be found in which resources served by Jetty remain available indefinitely.
This issue was tracked down to a Linux utility called tmpwatch, that is active by default in some Linux distributions. In its default configuration, it deletes content from the temporary directory 10 days after it was accessed last.
We've discussed two solutions:
Configure Jetty to use a different directory to store its temporary files.
Periodically iterate over all Jetty-generated temporary files, and reset they last modification date (mimicking the 'touch' command).