I am in the process of installing my streaming application on the test platform. There will therefore be multiple instances of the application (development, test, and later live). Is there any problem having multiple applications consuming the same stream? Also, there will be times when streaming will need to stop. E.g. during application updates, server maintenance, etc. During these periods, will we miss data, or will we receive it when the streamer restarts?
There is no problem having multiple applications consume the same stream - you just have multiple instances of the stream consumer consuming the same data. For the test instances I would recommend adding interaction.sample to your CSDL to reduce the number of interactions coming through your application (saving money!).
When you stop the application, unfortunately you will miss data. When we have implemented our Twitter Historics in the new year, you will be able to go back through old data and pick out anything you missed.