I have 3 x EX4100 and one EX4, connecting questions,backup synching

What I want to do is have 2 x ex4100 as my media servers using the NIC1(Using a gigbyte switch, yes I know my router has 4 connections but I have other stuff) and NIC2 as backup using the NAS External Backup option and synchronising. using a separate gigabyte switch not connected to the router or internet only to 2 other ex4100’s. or can I connect nic2 on the server directly to nic 2 on the backup nas with no switch, and if setting up an internal Network only, using ip 127 group or 172 group what advice would be given to make this work well if at all. Or do I have to have a computer included in the internal network to act as a gateway?

If I use a laptop through the wireless router using wd my cloud interface does the backup routing go through the laptop as it seems quite slow on some backups, I am backing up many TB’s of files so do not expect it done in minutes that’s why I like the synchronise option so it is only done once initially.

Do the 2 NIC’s on a EX4100 talk to each other as I am getting manifestations which suggest they do?

I have been experimenting so had a great backup going but it defaulted to ip group 169 which I read is a bad idea, so the backup now fails because I changed the ip grouping, is that possible, having set everything up matching properly it looks like disconnecting and connecting /changing the backup at all stops it updating/synchronising.

Would I be better off using internal backups and just spreading the collection around the 4 NAS’s, I was trying to avoid that as a NAS failure, I have them all set up as JBOD, no spanning or raid, might make the drives containing the data and the backups blow? Does moving hard drives around 4 WD Ex4100’s when they are JBOD work?

Lots of questions and I am sure I have some phraseology used incorrectly, this seems a great forum, and as an avid media collector I want to protect my collection and appreciate I should have and will have remote backups off site as well.

Thank you very much WD Community.

Okay update…I seem to have this working, by using nic1 on all 4 NAS through my router and switch and then NIC2 connecting directly for backups, the only issue I am encountering is , if I use the reboot option by sticking a pin in the back it resets the IP’s, bit tedious, if I reboot through the on line interface I do not know if that is different.