A disaster-recovery system contains a networked array of synchronous-to-asynchronous converter (SATC) modules that connect source databases to target backup databases. During backup, the system replicates each source-database transaction through a chain of these SATCs to a corresponding target, storing a local copy of the transaction on each SATC along the way. Each transaction's path between its source-target pair is identified by a set of tracking entries, where each entry identifies one SATC in the path. Before initiating a recovery operation, the system regenerates the tracking entries in order to reconstruct paths to source databases. The system then synchronously searches SATCs along each path for local copies of lost transactions that had not time to be fully replicated before the occurrence of a catastrophic failure. The full-blown recovery is started only after all lost transactions have been properly replicated to target databases.