Best backup solution

[inis]

I have a newer built freenas box, after building it I did so under sizing my new raid. I need to add another drive. I took my old freenas box 10 drive raid and got it installed into the machine, i had a drive going bad so I got it pulled and now down to 9x 3tb drives. What is the best method to back up my new raid (3x 8tb's) so I can add a new drive and rebuild it again. Currently machine is used for NAS and plex media server. I'm looking for minimal work to restore my plugin's. All drives are on one machine (currently 3x 8tb's (soon to be 4x) and 9x 3tb's. The 3tb drives are at there age limit so I don't want to be on them anymore than I have to be. Sorry if this is a repeat thread, i looked around but didn't find anything specific that assisted me meeting my goals.

 

[CraigD]