FileSync
The application FileSync keeps aligned the contents of two folders (source and destination), including all subfolders and files contained. The synchronization of these folders can be both locally and offsite.
The application (running in background) is configurable and records in a text file, with adjustable period, the operations of copy / deletion / overwriting on files / folders.
The performance are great, in fact during the files comparison / alignment operations, CPU and RAM remain below the 30%, and you can keep even a large number of files.
The program is free and is not available assistance. It's available a documentation file, downloadable with the program installation.
FileSync
Keep aligned the content of two folders.
Download: