= Server-side file deletion =
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 [http://boinc.berkeley.edu/files.php <file_info>]
 element for a file in a [http://boinc.berkeley.edu/tools_work.php 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.