Programmatically syncing with remote servers

Synching entire files has the tendency to create more traffic than you want. It may be a better option to do this on a finer-grained level, using your own RPC service.

For example, you could have a look at Apache Thrift. It basically allows you to create a remote service to do next to anything what you want. It works cross-language, cross-platform out of the box, designed to be efficient and based on a very simple IDL.

While creating your own service may involve some work, you are no longer bound to transferring entire files (but you can of course do that as well), you will also be able to extend the service in the future easily.

If you still want to exchange whole files, consider compressing them beforehand, and using services like dropbox, or the like. Depending on the "disclosure-level" of your data, you may additionally want to encrypt them during transfer.

I think you should accomplish two tasks:

1. watch source filesystem for change. This could be done by either cron job (task scheduler for windows) to check for changes, FTP watcher that checks changes in FTP server. I am sure there are other options too.
2. You have to copy source files to target servers. This you can achieve in many ways trough ftp or ssh or even upload files through http.

Your best setup depends on what is already installed there on servers or what is easier for you to set up. Also do you need to sync back if files have changes in remote servers.