During the design of Univa Short Jobs we realized that if a user submits a large workflow with many thousands of tasks and then those tasks are sent to a Launcher on a host very fast and then all tasks fail rapidly – it doesn’t take too much time, just a few seconds really, for the entire workflow to end up on this ‘bad’ host. We call these types of hosts ‘Black Holes’. They are somewhat like real Black Holes in that any task that is sent to it does not escape. It is also very hard to determine before you run the workflow if a host is a Black Hole, you don’t know until it starts to eat the tasks of your workflow. In Univa Short Jobs we have added a feature to detect Black Hole Hosts and ‘do something’. Watch this video to see how it works.