From the article:

1. Scale your database through database clustering

2. Scale your application, while leaving your existing database untouched by front-ending the database with In-Memory-Data-Grid (IMDG) or caching technologies. The database acts as a persistence store in the background. I refer to this approach as Persistence as a Service (PaaS).

Correct me if I am wrong but don't databases handle option 2 by themselves. In fact, isn't one of the primary purposes of a database that applications on top of them do not have to concern themselves with things like caching?

This reminds of another article where it pointed out two of the biggest mistakes with databases and one of them was the tendency to treat it like a dumb storage engine. This seems to be a classic case of that.