A flexible data transfer and data synchronization system is described. Local and geographically remote systems comprise a data processing network. Each remote and local system includes a data storage facility. The local system backs up, mirrors and/or synchronizes its data to one or several geographically remote systems. During normal operation the data is transferred between the local system and remote systems in an asynchronous manner. According to one aspect of the invention, should the local system be out of synchronization for any reason with the geographically remote system the two systems will automatically re-synchronize without interruption to local or remote system users. This includes the initial data transfer between the local and geographically remote system. Embodiments of the invention are based on the interception and queuing of file system events as they occur, rather than the interception and transmittal of actual data disk writes. In this way, embodiments of the invention it does not require temporary storage of the physical data disk writes themselves in a separate, possibly volatile buffer system.