The process of files getting corrupted owing to some hardware or software failure is called data corruption and this is among the main problems which hosting companies face because the larger a hard drive is and the more data is filed on it, the much more likely it is for data to get corrupted. You can find several fail-safes, yet often the information gets damaged silently, so neither the file system, nor the admins detect a thing. As a result, a damaged file will be handled as a standard one and if the hard disk drive is part of a RAID, that file will be duplicated on all other disk drives. Theoretically, this is done for redundancy, but in reality the damage will be worse. The moment a file gets corrupted, it will be partly or entirely unreadable, therefore a text file will not be readable, an image file will display a random mix of colors in case it opens at all and an archive will be impossible to unpack, and you risk losing your site content. Although the most widely used server file systems have various checks, they quite often fail to identify a problem early enough or require a long amount of time to be able to check all of the files and the hosting server will not be operational for the time being.