The process of files getting damaged resulting from 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 drive is and the more info is stored on it, the much more likely it is for data to get corrupted. You can find a couple of fail-safes, still often the information becomes corrupted silently, so neither the file system, nor the administrators see a thing. Thus, a bad file will be treated as a standard one and if the hard disk is part of a RAID, that particular file will be copied on all other disk drives. In theory, this is done for redundancy, but in reality the damage will get worse. Once a file gets corrupted, it will be partially or completely unreadable, so a text file will not be readable, an image file will display 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 well-known server file systems include various checks, they frequently fail to detect a problem early enough or require a vast period of time in order to check all of the files and the web server will not be operational for the time being.
No Data Corruption & Data Integrity in Semi-dedicated Servers
We've avoided any risk of files getting corrupted silently as the servers where your semi-dedicated server account will be created employ a powerful file system called ZFS. Its key advantage over alternative file systems is that it uses a unique checksum for each and every file - a digital fingerprint that's checked in real time. As we keep all content on numerous SSD drives, ZFS checks whether the fingerprint of a file on one drive corresponds to the one on the rest of the drives and the one it has saved. When there is a mismatch, the corrupted copy is replaced with a good one from one of the other drives and since it happens right away, there's no chance that a damaged copy can remain on our web servers or that it can be duplicated to the other drives in the RAID. None of the other file systems include such checks and what is more, even during a file system check after a sudden power failure, none of them can detect silently corrupted files. In contrast, ZFS does not crash after a power loss and the regular checksum monitoring makes a lenghty file system check obsolete.