Blackboard have a nice write up of useful log files to check here: https://en-us.help.blackboard.com/Learn/Administrator/Hosting/System_Management/Logs/002_System_Log_Descriptions
Following our upgrade to 9.1 Q4 2016 we found that in the tomcat stdout-stderr.logs were much larger. In fact they were about 30,000% larger than the same log on a 9.1 Q4 2015 server.
The logs were filled up with the following phrase repeated every 30 seconds:
We raised a ticket with Blackboard and my linux expert colleague Michael Nemetz also found a good link on stackoverflow http://stackoverflow.com/questions/23960451/java-system-preferences-under-different-users-in-linux
Blackboard told us this issue is due to be fixed in 9.1 Q2 2017 and agreed with the stackoverflow suggestion.
We resolved the issue doing the following:
and then restarting Blackboard.
N.B. I had tried using "pre" tags around the logs and the resolution above, but they ended up formatting in a long scrollable list and not very readable. So I made graphics instead.
-------->>>>>> Update <<<<--------
We found that this fix didn't work on our next Blackboard upgrade on a second dev server.
In the bb-config.properties file. With this we could remove our previous fix.