By default, all of the files used by Analysis Services to store MOLAP data are stored in the Analysis Services data directory. The location of this directory is set up during installation, and can be changed by setting the value of the DataDir server property.

As with any other type of file handled by Windows, the files in the Analysis Services data directory are prone to fragmentation. During processing, many files are created, written, and deleted. If the disk is very fragmented, these files may be split across different portions of the disk, slowing down access to them.

A regular defragmentation of the drive on which the data directory exists will improve the overall speed of the disk subsystem, which will of course have benefits for Analysis Services query and processing performance. As a result, we suggest regular disk defragmentation of the Analysis Services data directory's drive as part of the server's maintenance plan, making sure of course that it...