Best way to add data to array

So the system I will be putting unRAID on is my only system at the current time. Which way would be a better way to load data into the array once it's created: mounting the drives in unRAID outside of the array and transferring data that way, or transferring data via the network from another system. I know my unRAID system supports gigabit Ethernet, I do believe the other system I can get set up has gigabit support as well...

enable turbo write, then use either way of  transferring data. They'll probably be about the same speed. If the files are already on the network, then set it up and go get a coffee...pizza... whatever.

You first say unRAID is your only system, then you ask about transferring over network from another system.

The main reason I am replying though is to ask whether you have backups. Since you say you only have one system I am concerned that you will not have other copies of your critical and irreplaceable files on another system. unRAID parity is no substitute for backups.