Ayende, the creator of RavenDB:
Typically, it isn’t the only database in the project. In brown field projects, we usually see RavenDB brought in to serve as a persistent view model store for the critical pages, data is replicated to RavenDB from the main database and then read directly from RavenDB in order to process the perf critical pages. For green field projects, we usually see RavenDB used as the primary application database, most or all of the data resides inside RavenDB. In some cases, there is also an additional reporting database as well.
So the quick answer, and the one we are following, is that RavenDB is imminently suitable for OLTP applications, and can be used with great success as a persistent view model cache.
You’d be right say that this is an answer that could be used for most of the NoSQL databases. Looking back at their history, most of the NoSQL databases have started as ways to address problems that people in the field have been having with relational databases. Thus NoSQL databases were mostly used together or at least in the same environment with the relational databases or other storage solutions. Also considering NoSQL databases are an evolving technology, not everyone dropped their existing data stores and started to use them.
Adding NoSQL technologies to existing stacks is the leanest adoption path and the one that minimizes risks. Not to mention that this is the way to accumulate experience with them without putting at risk your business.
Now going back to RavenDB, there are a few titillating features that might arouse your curiosity.
Original title and link: When to Use RavenDB? ( ©myNoSQL)