Após mais 3 horas de execução do Google, eu encontrei novamente: link
Por que eu estava procurando por uma ferramenta como essa:
DisParity is a free backup utility that calculates parity from data on multiple hard drives. If one of the drives fails, disParity can use the previously calculated parity data, in combination with the remaining drives, to recover the contents of the lost drive. It's a fast, free and easy way to protect yourself against data loss caused by hard drive failures on home media servers.
The concept is similar to RAID, but no specialized hardware is required. Unlike traditional hardware RAID solutions, there is no limit on the number of drives that can be protected, and no requirement that all drives be the same size, or even on the same PC. The approach used by disParity is sometimes referred to as "software RAID" or "snapshot RAID", because the utility operates on a fixed snapshot of the hard drive data taken at a particular time. Because of this, it is not suitable for use on drives where files are changing frequently, such as database servers. It is perfect, however, for applications such as multi-terabyte home media servers, where files change infrequently.