Need help on shared file system
 

Scenario : One Machine has 500 GB Storage. Second machine has 80 GB Storage. Made private and public networks(Used two Network cards in LAN). All are communicating.

Problem : Need to make the storage 300GB (Out of 500 GB) of Machine 1 as shared storage. How can we do that?

It would seem obvious that you need to create the 300GB partition, then share it with other machines. How you do this depends on what you're working with, and you provide no details. You don't tell us what the machines are running (OS? Distro? Version?), which will not only determine how to configure things, but which may be best. The two most common are NFS and Samba, which can share resources between machines.

Unless you provide details, no one can help you. And your previous posts say you've been an administrator/professor for two years now, with a Red Hat certification. Both of these things should be trivial for you to set up.