We've been having some serious performance issues here at Liverpool quite recently and despite working closely with Blackboard, so far, we have not been able to identify a trend with when they occur.
What we've seen happen is a sudden backlog of database queries targeting the announcements table which eventually overloads the database and causes the whole system to grind to a halt. This has happen 3 or 4 times over the last month now and has caused some significant interruptions to exams.
As a temporary measure we have now disabled the My Announcements tool which we have on our Blackboard landing page which we're told should prevent the issue from happening again while it is being investigated.
I'm wondering how many other self hosted institutions make use of this feature and whether anyone has ever come across anything similar?