A Survey on File Defragmentation Techniques on Modern Storage Systems.

File fragmentation is one of the widely studied subjects for several decades due to its considerable degradation on I/O operations. Also, it is a well-known problem in academia that file fragmentation on HDD disks can extremely lower the throughput and increase tail latency. However, even with modern storage devices, such as flash-based SSDs and Optane SSDs, the highly fragmented file systems shows considerable underutilization of the storage device. Due to the different nature of the modern storage systems in comparison to the conventional disks, the fragmentation is often called ‘aging’. This paper shows an overview of the aging of modern storage devices and their fragmentation effects. Also shows the survey of file fragmentation and its related literature, showing the studies discovering fragmentation in file systems, and mitigation techniques which suitable for modern storage devices.