In computing, file system fragmentation, sometimes called file system aging, is the tendency of a file system to lay out the contents of files non-continuously to allow in-place modification of their contents. It is a special case of data fragmentation. File system fragmentation negatively impacts seek time in spinning storage media, which is known to hinder throughput. Fragmentation can be remedied by re-organizing files and free space back into contiguous areas, a process called defragmentation.
Solid-state drives do not physically seek, so their non-sequential data access is hundreds of times faster than moving drives, making fragmentation less of an issue. It is recommended to not manually defragment solid-state storage, because this can prematurely wear drives via unnecessary write–erase operations.[1]