Cross linking multiple Synology NASs

[Analog Kid]

What's the best way of cross connecting NAS units so they can talk to each other without using the primary network interface?

For reasons that I can't fully explain, I have 3 Synology NAS units each with 4 ethernet ports on the back. All running DSM7, all connected through a switch to the main network. Now I need to shuffle a bunch of files between them.

First shot was just doing a copy from Finder, which is convenient for little stuff, but for big stuff forces all the data to come to my machine over the 1Gb link and then back out to the second machine over the same 1Gb link which causes a bunch of network bottle necks.

Second approach was to mount them as shared drives on each other and do the copy from DSM, which works but it's still using the primary network interface and competes for resources with other transactions.

Can I just use some of the remaining ethernet ports to create point to point network connections between them? How little messing around with DHCP and DNS can I get away with? Am I going to have to setup alternate server names for the secondary network so they know which port to communicate over?

 

[Analog Kid]

Looks like maybe static IPs all around is the way to go. Not as friendly, but gets the job done, and it's not like I'm going to be plugging devices in and out so automatically recognizing each other isn't critical. The main reason doing it by name would be nice is because I don't expect to have to look at this again for a long time, so doing it all by naming helps self-document the setup.