The process of files getting corrupted owing to some hardware or software failure is called data corruption and this is one of the main problems that 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 be corrupted. You will find a couple of fail-safes, but often the information gets damaged silently, so neither the file system, nor the admins see a thing. As a result, a damaged file will be handled as a good one and if the hard drive is part of a RAID, that particular file will be copied on all other drives. In theory, this is for redundancy, but in reality the damage will get worse. When a file gets corrupted, it will be partly or entirely unreadable, so 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 will be impossible to unpack, so you risk sacrificing your content. Although the most popular server file systems feature various checks, they frequently fail to identify a problem early enough or require a long amount of time in order to check all of the files and the web hosting server will not be functional in the meantime.