It's fascinating to read another company having evaluated NoSQL and come to an identical conclusion as we did internally.
I love the idea of NoSQL, but Cassandra was horrible (just look their source code or Thrift) and Mongo lost data. I guess 40 years of relational databases isn't so easy to replace.
To be clear, we are still heavy users of Cassandra. We try and objectively match the tool to the problem and in some cases, PostgreSQL was a better fit but not all. In some cases HBase was a better fit.
Also to be clear, scaling is difficult, no matter what the tool. We've had problems with Cassandra, HBase and PostgreSQL (most recently Friday), no storage option is as good as we would like under stress.
I definitely could have been more clear on that. Cassandra has so many great properties, and when we made the decision to use Postgres for the large dataset under question was shortly after 0.7 was released, and it took a while to get more stable.
I love the idea of NoSQL, but Cassandra was horrible (just look their source code or Thrift) and Mongo lost data. I guess 40 years of relational databases isn't so easy to replace.