What happened to ANGEL early this semester?
Three factors contributed to inconsistent ANGEL service and temporary unavailability during the beginning of FS09:
- An unexpected change in usage patterns.
- An increase in concurrent users of the system.
- The software upgrade to ANGEL 7.4.
The software upgrade specifically placed unforeseen stress on the system's database. If the database has issues, the ANGEL user experience suffers, to the point where the system can become unusable. Our initial projections and observations for the fall semester showed the original database server (8 CPUs with 32G of RAM) had sufficient capacity and would adequately manage the expected load of 6,000 concurrent users at the start of the semester. During the second week of the semester, this proved to be untrue. The database server was overwhelmed by the new peak load of 7,500 concurrent users.
After working with Blackboard/ANGEL Learning, we realized it was not solely an issue with the application software as originally suspected. The next step we took was to replace the database server with a newer, faster machine (16 CPUs with 64G of RAM). Once the database server was replaced, we immediately began to see concurrent usage in the 6,500 to 7,500 user range with peaks as high as 9,000 concurrent users. These new peaks, and new usage patterns in fact, led us to install additional web servers, allowing us to better manage and sustain higher usage.
What's the current state of ANGEL? Are there still performance problems?
At this time, the remaining issues users are experiencing are related to the 7.4 software upgrade. Many of these bugs are already known and are currently being addressed by the vendor. Any user currently experiencing issues with ANGEL should contact Distance Learning Services at (517) 355-2345. There are no system-wide performance issues with the service at this time.
What is being done now?
We continue to actively monitor ANGEL for any issues, watching for signs of performance degradation or instability. We are also looking at options for increasing the performance of the underlying hardware that the service runs on. Possibilities include new file servers and adding even more web servers.