One feature of SFS that is almost unique among Amiga filesystems is its ability to defragment itself while the filesystem is in use, even for locked files. The defragmentation process is almost completely stateless (apart from the location it is working on), which means it can be stopped and started instantly. During defragmentation data integrity is ensured of both meta data and normal data. The filesystem may attempt to move a whole file to a different location when fragmentation is going to occur otherwise.