Hi, we just migrated all data from mongo100(verion 2.6.12) to mongo200(version 4.2.3). That means mongo100 is not getting or serving data anymore. ALL customers running now on the new mongo200. Tests showed that performance and space savings due to the new wiredtiger engine and filesystem inline compression are significant. We do not touch the old Data from mongo100 and mongo200 for serval weeks until we know that this new setup runs stable so we are able to switch back to old system very fast. We will shutdown the mongo100 in the far future because this is real hardware and we have plans for reusing this hardware for internal glusterfs Storage. Thanks to Sören for the new php mongo driver integration which made this upgrade possible. Thanks to Carsten for supporting this migration. BR Denny