[getcrunk]

I just read the original article my self before seeing your post. The last bit about "sharding" by partitioning your db from the start helped alleviate a lot of my concern I think. All my apps data doesn't actually need to be in the same DB for 90% of my use case (userid in range -> db x).

[xupybd]

You may be able to setup a multi tenant db. I've done this in the past. A new schema was created for each tenant. It worked well. It never got to the size where it had to scale out. So not sure how easy it would have been to move to multiple databases.