The most appealing feature of many NoSQL databases, for me, is their ability to automatically shard and replicate data across multiple instances. It is possible

The most appealing feature of many NoSQL databases, for me, is their ability to automatically shard and replicate data across multiple instances. It is possible to do this with relational databases such as Postgresql, but it is not easy from my experience. Also failover and balancing sharded data are not things that are easy with relational databases.