I work for Kaplan International and several of our Moodle instances are randomly logging users out. This mainly seems to happen when there is a high amount of load on the servers.
We are currently running Moodle 2.6.3 and we use the Memcached Session Handler.
We've are not quite sure what's causing this to happen. However, the problem doesn't seem to happen when we use the Database Session Handler. Leading us to believe that this is something to do with Moodle's Memcached Session Handler.
We started using Memcached on an ElasticCache (single node) instance. But, when we started noticing this issue we installed Memcached locally on the Web servers and used Sticky sessions to keep the users on a single instance. This has reduced the frequency of the issue, but, it continues to affect users.
All our instances are hosted on AWS. The environment details are as follows:
Session Handler: Memcached
Has anyone else come across this issue? Please let me know if you need any more details?