I have been working on some pretty large projects lately - tables with millions of records in the database, over a million PDF documents stored in the database, etc.  We have a pretty large training system running on DNN - several hundred thousand records in some table and some definite spiking in usage depending on different times.  I am curious how many large scale DNN implementations are out there and what work has been done to ensure performance, scalability, ease of management, multi-server content staging, etc.  To me these are the issues that will need to be addressed down the road by DNN versions, 6, 7, 8, etc.