TrueNAS

The answer to this is a little more dependent on what you have running on your primary. If it's solely a file share, then yes. Rsync can be used to simply mirror your pool from one host to another, effectively making a mirror copy.

If you are running applications like jails, plugins, etc, then this answer can sometimes become more complex. Sometimes those applications, jails, whatever only need to have their files copied, which might mean you have to create the application on your backup and then restore the files.

Certain applications that are more complex are affected by a concept called crash consistency. If something uses a database or vm that's reading and writing, when you copy the database it may not be consistent meaning there are things in the middle of being read and written. And that case you needed to have the application stop finish all of its operations and then copy the files. This is likely more complex for may not be applicable to your situation.

If you want to ask specific questions about restoring applications, jails, VMS on trunaz, I would suggest hitting up the trunez community forum after you read the manual a couple of times, they'll eat your lunch if you ask a question that could be simply answered by reading the manual