Now that 2TB USB HDDs are all over, for cheap, will that do? You can start the backup (your choice how, there is rarely a wrong choice but beware those that want the best (it's a trap) solution.)
As to the connection of the hard drives YOU NEVER TOUCH THAT UNTIL you have backup copies.
As to the network, it works so you don't touch until all is on backups (plural.)
My hobby club has a RAID drive array that is network connected to the one PC that is used by the club to house an archive of our scanned photgraphs and documents. I am looking for recommendations on how to be back up the drives as they are today. I would also like recommendations on how to better configure the connection of the archive database on hard drives. (I suspect using the current network set-up is not the most effective).