I am looking for if cassandra has limitations of node hardware spec like what could be the max storage per node if there is any such limitation.
I intend to use couple o
Cassandra distributes its data by row, so the only hard limitation is that a row must be able to fit on a single node.
So the short answer is no.
The longer answer is that you'll want to make sure that you're setting up a separate storage area for your permanent data and your commit logs.
One other thing to keep in mind is that you'll still run into seek speed issues. One of the nice things about Cassandra is that you don't need to have a single node with that much data (and in fact its probably not well advised, you're storage will outpace your processing power). If you use smaller nodes (hard drive space wise) then your storage and processing capabilities will scale together.