When your data store is defragmented, PerfectDisk creates a separate working copy in a temporary directory, and then copies this file back over the original data store. To create this working copy of the Exchange data store, there must first be sufficient space on your target hard drive.
Defragmenting an Exchange data store requires free space equal to 110% of the original data store size. You can figure that amounts to about 11 GB for every 10 GB, or 110 GB for every 100 GB of space in a data store. By default, PerfectDisk will use the boot drive containing the Windows installation path.
Related Topics
§ How long does it take to defragment an Exchange data store?
§ How often should I defragment an Exchange data store?
§ What versions of Exchange Server does PerfectDisk support?