Hi Gustaf,
Yes, everything you have said is what we are experiencing and it looks like the data is showing that too.
Yes, focusing on -expire 500ms would be a good place to start - to see why it is not honored in these cases.
As for the last three questions you asked:
Do you have any information, what was the case with the jira system in this time window (hanging, overloaded, crashed)?
Answer: The Jira system was hanging and/or overloaded during the time frames above.
Talks NaviServer directly with jira, or is there a server between (e.g. a reverse proxy, or a load balancer).
Answer: We are talking directly to JIRA -- there is no proxy and no load balancer involved.
What was the time window, when NaviServer hast stopped serving requests? Did it recover by itself, or did you restart it?
Answer: We never did restart naviserver on Jan 4th - it recovered by it's self after JIRA was restarted.
Answer: Naviserver was un-responsive starting at 13:24pm - 13:31pm. Then we started to getting connections again at 13:32pm.