Why NoSQL is better at “scaling out” than RDBMS?

Question

I have read the following text in a technical blog discussing the advantages and disadvantages of NoSQL

\" For years, in order to improve performanc

Answer 1

In RDBMS when the data becomes huge then it may happen that tables are spread across multiple systems and in that case performing operations like JOIN are very slow.

In case of NoSQL in general related data are stored together on same machine (either in single document - in document oriented databases or in case of Wide column datastore the related columns are on same machine). Hence its easy to scale out on a number of low end machines, obviously in this case there will be duplicate data in multiple places which is not the case in RDBMS