Good afternoon.  Looking at the documentation, it appears that the Unix File System agent is supported for Intellisnap with the HP 3PAR StorServe array is.  

https://documentation.commvault.com/2022e/essential/106164_supported_arrays_and_agents.html

As to your other question: 
“If yes does it will cause any harm to data while doing testing of backup.” 

There is no harm to data while testing.

Thanks. But somewhere in the documentation, I see ubuntu 18.x and later versions are not supported.