The process of files getting damaged due to some hardware or software failure is called data corruption and this is one of the main problems which Internet hosting companies face as the larger a hard disk drive is and the more info is placed on it, the much more likely it is for data to get corrupted. There're different fail-safes, still often the information gets damaged silently, so neither the particular file system, nor the admins see a thing. Because of this, a corrupted file will be handled as a standard one and if the hard disk is a part of a RAID, that file will be copied on all other disk drives. In theory, this is done for redundancy, but in practice the damage will get even worse. The moment some file gets corrupted, it will be partially or completely unreadable, therefore a text file will no longer be readable, an image file will present a random mix of colors if it opens at all and an archive shall be impossible to unpack, so you risk sacrificing your site content. Although the most widely used server file systems include various checks, they often fail to discover some problem early enough or require an extensive amount of time to check all files and the web hosting server will not be functional for the time being.