svnadmin list-unused-dblogs — Ask Berkeley DB which logfiles can be safely
          deleted (applies only to repositories using the
          bdb backend).
Berkeley DB creates logs of all changes to the
            repository, which allow it to recover in the face of
            catastrophe.  Unless you enable
            DB_LOG_AUTOREMOVE, the logfiles
            accumulate, although most are no longer used and can be
            deleted to reclaim disk space.  See the section called “Managing Disk Space” for more
            information.