Files are deleted from the data server's upload and download directories by the file_deleter daemon. Typically you don't need to customize this. The default file deletion policy is:

    * A workunit's input files are deleted when all results are 'over' (reported or timed out) and the workunit is assimilated.
    * A result's output files are deleted after the workunit is assimilated. The canonical result is handled differently, since its output files may be needed to validate results that are reported after assimilation; hence its files are deleted only when all results are over, and all successful results have been validated. 

Command-line options are:

-preserve_wu_files 	Don't delete input files
-preserve_result_files 	Don't delete output files
-retry_errors 	Retry file deletions that failed previously.
-delete_antiques 	periodically (once per hour) removes any files in the upload/ directory that are older than the oldest WU in the database. These files are created when BOINC clients return work really late after the deadline -- so late that the corresponding WU has been deleted from the database.

In some cases you may not want files to be deleted. There are three ways to accomplish this:

    * Run the file_deleter daemon with the -preserve_wu_files and/or the -preserve_result_files command-line options.
    * Include <no_delete/> in the <file_info> element for a file in a workunit or result template. This lets you suppress deletion on a file-by-file basis.
    * Include nodelete in the workunit name. 

You may need to implement your own scheme for deleting files, to avoid overflowing data server storage.