If I have three systems I want to synchronise and I don’t know which ones will be running or not at any particular time is it OK to synchronise ‘all to all’ as it were?
I don’t do this at the moment but I have one case where I want to be really sure that files are on all three systems as quickly and reliably as possible and so syncing all of them with each other would make sense as long as there aren’t any possible issues.
There will only be one user (me) so changes will almost certainly only happen on one system at a time.
I’d say there should be no issues. Of course, you need to be careful not to edit the same files on multiple devices before the previous edits have had a chance to synchronise.
That said, I personally prefer to have at least one device online all the time. It’s not really a “server”, but it does play such a role in reality. In my case, this is just my home computer, but a person I know uses their phone for this very purpose (since the phone is always on and also always connected).
Yes, for all my other synchronisation I use my home desktop machine as the ‘hub’ with all others only connected to that machine.
However in this new case I’m synchronising a laptop, a phone and the home desktop. Very frequently it may be that the laptop and phone are on the same LAN but a long way (internet wise) from the home desktop. So it would seem sensible to allow changes to go direct between laptop and phone.
Distance (or rather latency) does not matter much, unless you have big changes all the time. The best thing you can do is connect them all to each other.