When using filesystem attachments with attachment versioning disabled, deleted attachments are duplicated on the hard disk.

#-# The attachment storage.
xwiki.store.attachment.hint=file
#-# The document versioning storage.
# xwiki.store.versioning.hint=default
#-# The attachment versioning storage. Use 'void' to disable attachment versioning.
xwiki.store.attachment.versioning.hint=void
#-# The document recycle bin storage.
# xwiki.store.recyclebin.hint=default
#-# The attachment recycle bin storage.
xwiki.store.attachment.recyclebin.hint=file