Design patterns involving Spark

[Ashok Kumar]

Hi,
There are design patterns that use Spark extensively. I am new to this area so 
I would appreciate if someone explains where Spark fits in especially within 
faster or streaming use case.
What are the best practices involving Spark. Is it always best to deploy it for 
processing engine, 
For example when we have a pattern 
Input Data -> Data in Motion -> Processing -> Storage 
Where does Spark best fit in.
Thanking you