Hey, do you have customer instances where the app is on non-aws bare metal ( like Softlayer) and the db is on heroku postgres? What are the pros and cons of this scenario?
Absolutely. Basically, as long as your app is running somewhere with Very Good Latency to your database, this can be a fine pattern. In practice, this means if the data center is also in Ashburn, Virginia, and better yet, has a DirectConnect deal set up with AWS, you should be in business. The best way to test this is to provision a database and see how latency from your app is. My opinion is that 5ms latency would be a ceiling on what I'd tolerate for my own apps, and I'd probably look for more like 1-2ms or better.
