The MD Storage Manager Software uses the virtual disk I/O characteristics to determine the appropriate segment size and for a virtual disk. Choose the virtual disk I/O characteristic that matches your storage requirements. You can choose from multimedia, database, or file system. The typical virtual disk I/O characteristic is file system. When you choose one of the virtual disk I/O characteristics, cache prefetch is turned on or turned off and the corresponding segment size is set. You cannot make changes to these settings.