The process of files getting corrupted as a consequence of some hardware or software failure is referred to as data corruption and this is among the main problems which web hosting companies face because the larger a hard disk drive is and the more data is kept on it, the more likely it is for data to become corrupted. There're different fail-safes, but often the information becomes damaged silently, so neither the particular file system, nor the administrators notice a thing. Because of this, a corrupted file will be treated as a good one and if the HDD is part of a RAID, that particular file will be duplicated on all other drives. In theory, this is for redundancy, but in practice the damage will get worse. Once a file gets corrupted, it will be partly or completely unreadable, so a text file will not 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, and you risk sacrificing your content. Although the most widespread server file systems feature various checks, they often fail to discover a problem early enough or require an extensive amount of time to be able to check all of the files and the web server will not be operational in the meantime.