How does spark work?

[陈卓]

Hi
I'm a newbie.
In my spark cluster, there are 5 machines, each machine 16G memory, but my data 
may be more than 900G, the source may be HDFS or mongodb, I want to know how to 
put this 900G data into spark cluster memory because I have a total memory 
space of 80G. How does spark work?




Thanks!
Jetty