The process of files getting corrupted resulting from some hardware or software failure is known as 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. You'll find different fail-safes, but often the information gets corrupted silently, so neither the particular file system, nor the admins notice anything. Thus, a damaged file will be handled as a standard one and if the HDD is a part of a RAID, that particular file will be duplicated on all other disk drives. In theory, this is done for redundancy, but in practice the damage will be worse. When some file gets damaged, it will be partially or completely unreadable, which means that a text file will no longer be readable, an image file will present a random combination of colors if it opens at all and an archive shall be impossible to unpack, so you risk sacrificing your website content. Although the most widespread server file systems feature various checks, they often fail to identify some problem early enough or require a long time period to check all the files and the server will not be operational for the time being.