Nice work guys, that works well. I have some suggestions for you ;)
It would be good if the date range was passed through to the individual app when you clicked through from the main dashboard. Also add some more date ranges to the dropdown like 1 hour, 6 hours, 12 hours, etc.
Bonus points: a date range picker on the app dashboard would be awesome - it would be easier than trying to choose e.g. 24 hours on the graph. And it could remember your selection - i.e. seeing errors over 2 weeks isn't that useful for us as a default view, we're more interested in the last 24 hours, or what's happened overnight.