As files are created, modified, and moved, fragmentation can occur both within the volume's allocation table and on the volume itself. This happens because files are written to clusters on disk as they are used. The file system uses the first clusters available when writing new data, so as you modify files, different parts of files can end up in different areas of the disk. If you delete a file, an area of the disk is made available, but it might not be big enough to store the next file that is created and as a result, part of a new file might get written to this newly freed area and part of it might get written somewhere else on the disk.
Although the file system doesn't care if the file data is on contiguous clusters or spread out across the disk, the fact that data is in different areas of the disk can slow down read/write operations. This means it will take longer than usual to open and save files. It also makes it more difficult to recover files in case of serious disk error. Windows Server 2003 provides a tool for defragmenting volumes called the Disk Defragmenter.
Was this article helpful?