You must specify a work directory the Integration Service uses to create temporary files while it sorts data. After the Integration Service sorts the data, it deletes the temporary files. You can specify any directory on the Integration Service machine to use as a work directory. By default, the Integration Service uses the value specified for the $PMTempDir process variable.
When you partition a session with a Sorter transformation, you can specify a different work directory for each partition in the pipeline. To increase session performance, specify work directories on physically separate disks on the Integration Service system.