The process of files being corrupted as a result of some hardware or software failure is called data corruption and this is among the main problems which web hosting companies face because the larger a hard disk is and the more information is stored on it, the more likely it is for data to be corrupted. There're several fail-safes, yet often the info is damaged silently, so neither the file system, nor the administrators see a thing. Consequently, a damaged file will be treated as a good one and if the hard disk is part of a RAID, that particular file will be duplicated on all other disk drives. Theoretically, this is for redundancy, but in reality the damage will get worse. The moment a given file gets damaged, it will be partially or entirely unreadable, therefore a text file will no longer be readable, an image file will display a random blend of colors in case it opens at all and an archive will be impossible to unpack, and you risk losing your website content. Although the most widely used server file systems feature various checks, they often fail to find some problem early enough or require a vast time period in order to check all the files and the server will not be functional in the meantime.