Here in Partners in Health, Rwanda, Sync 1.0 has been central to our service since ~2011. I'll summarize here a bit of our experience. Advancement of this functionality comes up continually for us both for our own sites (~45) and across the country of Rwanda.
We have two sync networks, one with 25 children and the other with 20. These networks sync our modules, configurations, and html forms as well as patient data. Currently, patient data is synced up to the central server and then that same data is snyced down to each server.
The servers are connected to each other either through the internet or a cellular modem-based APN connecting the rural servers.
Sync has been central to our ability to capture information from our clinical programs and do central reporting. However, it has been very costly in maintenance time to do so.
In Rwanda, we have significant issue with uptime to our rural servers trying to connect but only doing so intermittently. This is an even larger issue when these child servers must be accessed for certain data or fixes.
Historically, the largest problem with Sync 1.0 had been the number of sync errors. Each sync error completely stopped the serial transmission of data in that direction from that server. These then had to be fixed by one of our developers--a particularly difficult task on difficult-to-access rural servers.
To keep the amount of data sent more reasonable, we partitioned the network into two parts. We would prefer to have a single network and the country of Rwanda would like to be able to capture information from around the whole country.
From time to time we simply bring all the servers to a central point to do more fundamental updates and to get an updated sync.
Echoing Ellen and Mike, improved sync would be of great value to us here in PIH-Rwanda and we'd be happy to share more of our experience.