If you don’t mind the complexity overhead, or the possible security risk it necessitates opening up, it is possible to get the single bay units to start rsync in daemon mode.
Alternatively, you could create a secure VPN tunnel using a VPN solution of your choosing, and then alleviate the security vulnerability aspects of leaving the necessary ports open.
WDSync (through the WD server back-end) leverages an OpenVPN client install that is baked into these units. It works by having the MyCloud create a stateful connection with a known host (WD’s server farm), which is how it gets past end user NAT firewalls. That stateful connection sustains the VPN tunnel. Your remote devices/workstations get a session token, and authenticate security credentials against WD’s server backend, and that backend then serves as the arbitrator between both ends of the connection. When used locally, it just talks directly to the box using a custom daemon running on them.
How you would choose to proceed is entirely up to you. There are pros and cons with every possible way you could approach this. Finding the right balance is not something any of us here are really qualified to attempt; It’s YOUR network, and YOUR data.
We can just help you along once you have made some choices.
If your sync needs are entirely local to your network, with no internet-traversing links, then daemonized rsync is probably what you would find most favorable.
The Gen1 single bay units are easy enough to convince to run rsync in this fashion, since they have a persistent root volume, and use /etc/init.d.
The Gen2 units are more troublesome, but can be made tractable, if you dont mind voiding your warranty. (WD does not like it when you make modifications of the nature needed to have reliable user scripts run on the gen2. They went out of their way to make it difficult to do in the first place.) For that, you will need to install the WDCrack package from Fox_Exe using his instructions, then you need to insert your routine to start rsync in daemon mode in its initialization script. It will then execute on every system boot after the unit fully comes up, at the very last stages of startup.
Once running in daemon mode, you can connect to it directly using rsync from any host that supports rsync. (Unix, Linux, OSX, etc— and windows with an appropriate client or utility.)
If your sync needs require traversing the internet, you can still choose to use daemonized rsync, but with appropriate ports made open (If you accept the security risk this introduces) or you can find some kind of VPN that suits your needs.
