[Deploying Sakai] Zombie sessions associated with WebDAV

[Seth Theriault]

Hello,

In a CLE call a few weeks ago, I mentioned that Columbia is seeing a
large number of "zombie" sessions reported in the Online tool. For
example, our local Sakai is currently reporting more than 163,000
sessions, a clearly incorrect number since it is 5x the number of
eligible users. In addition, the Apache logs confirm that these
sessions are simply orphaned because there is no corresponding HTTP
traffic; every once in a while, Sakai moves to close some of them.

This is 2.8.1 with local modifications. We started to see this
behavior in January after an local upgrade, so we have suspected that
a change to the local modifications is that the core of the problem,
but no obvious things have revealed themselves. In addition, this JIRA
shows similar behavior, but isn't restricted to WebDAV sessions:

https://jira.sakaiproject.org/browse/KNL-1035

Has anyone else seen this sort of behavior? Does anyone have any ideas
about where the problems might be? The DAV module is notoriously
problematic -- especially with the native OS clients -- so I am
thinking that's the prime candidate.

Seth