Hello, I migrated my OpenLDAP data from bdb to mdb in a Multi-Master Replication architecture that is working for years now. Unfortunately using only 2.4.31-2+deb7u2 from Debian 7. In the 2nd server (yyyyyy in the configuration below), I noticed new log lines for each LDAP entry. nonpresent_callback: rid=002 present UUID 345d766c-b2d5-1030-9b6b-85786c41386a, dn uid=tve0320,ou=people,dc=univ-tlse2,dc=fr It occurs if the server yyyyyy is down, a modification is done on the server xxxxx and yyyy is started. I saw it's related to the "PRESENT" step on replication. I haven't the sync logs for long so I cannot say if it happened with the previous backend. So, is this a warning about a data problem or does it only mean "I'm looking for the existence on rid=002 and that's fine, here are the UUID and dn" ? Here is part of my conf, also replicated : /etc/ldap/slapd.d/cn=config.ldif:olcServerID: 1 ldap://xxxxxxx/ /etc/ldap/slapd.d/cn=config.ldif:olcServerID: 2 ldap://yyyyyyy/ olcSyncrepl: {0}rid=002 provider=ldap://xxxxxxx/ binddn="--------" bindmethod=simple credentials=----  searchbase="dc=univ-tlse2,dc=fr" type=refreshAndPersist retry="5 5 300 +" attrs="*,+" tls_reqcert=never olcSyncrepl: {1}rid=003 provider=ldap://yyyyyyy/ binddn="--------" bindmethod=simple credentials=----  searchbase="dc=univ-tlse2,dc=fr" type=refreshAndPersist retry="5 5 300 +" attrs="*,+" tls_reqcert=never olcMirrorMode: TRUE olcDbCacheSize: 10000 olcDbCheckpoint: 512 5 olcDbNoSync: TRUE olcDbMaxSize: 3221225472 olcIndex: entryUUID,entryCSN,contextCSN eq Thanks for your advices, Florent Lartet University of Toulouse Jean Jaurès