My team, which consists of network architects and developers has been running Scrum for the past couple of months and the biggest issue we have is how we're supposed to record BAU work.
We consider BAU work to be things that are repeatable (i.e. provisioning a new user account) that we have to do from time to time that do not relate to our project at all. We can't give these tasks to people outside of the project because we're a small team and have day to day functions outside of the project.
We use a JIRA project to run our Sprints and have considered using Trello or another JIRA project to keep track of our BAU work. We haven't implemented any of these yet since we're still mulling over potential options and haven't identified success criteria yet.