+To update checksums asynchronously, enable the queue, install snf-pithos-tools and use ``pithos-dispatcher``::
+
+ pithos-dispatcher --exchange=pithos --key=pithos.object --callback=pithos.api.dispatch.update_md5
+
+To send sharing notifications::
+
+ pithos-dispatcher --exchange=pithos --key=pithos.sharing --callback=pithos.api.dispatch.send_sharing_notification
+