Fragmentation is the name given to a phenomenon that can be observed when a partition or logical volume is used over a longer period of time. In general, such a volume has a common file system. When data is written, the file system will try to keep logical blocks together as much as possible, using free space on the file system when this is available. When this is not possible, a file will be split into parts, which will be written to the volume. As the file is not stored in one part, accessing it will take a little longer. A process that saves all the files in one part per file is called defragmentation. 