This is most likely a "load" related problem since we never experience this problem in the testlab, only production.:
Apr 23 20:36:37 ldap01 slapd2.4[32233]: bdb_dn2entry("macaddress=1\2C6\2C00:00:00:00:00:01,ou=xxx,ou=xx,o=xxxx")
Apr 23 20:36:37 ldap01 slapd2.4[32233]: => bdb_dn2id("macaddress=1\2C6\2C00:00:00:00:00:01,ou=xxx,ou=xx,o=xxxx")
Apr 23 20:36:37 ldap01 slapd2.4[32233]: <= bdb_dn2id: get failed: DB_NOTFOUND: No matching key/data pair found (-30988)
Apr 23 20:36:37 ldap01 slapd2.4[32233]: => bdb_dn2id_add 0x2fed7: "macaddress=1\2C6\2C00:00:00:00:00:01,ou=xxx,ou=xx,o=xxxx"
Apr 23 20:37:44 ldap01 slapd2.4[32233]: slap_listener_activate(8):
Apr 23 21:35:42 ldap01 slapd2.4[32233]: connection_close: conn=1025 sd=16
Apr 23 21:55:42 ldap01 slapd2.4[32233]: connection_close: conn=1022 sd=17
Apr 23 21:55:42 ldap01 slapd2.4[32233]: connection_close: conn=1037 sd=18
Apr 23 21:55:42 ldap01 slapd2.4[32233]: connection_close: conn=1038 sd=20
Apr 23 21:55:42 ldap01 slapd2.4[32233]: connection_close: conn=1039 sd=25
Apr 24 12:02:23 ldap01 slapd2.4[32233]: daemon: shutdown requested and initiated. I have two Centos 5 servers running Openldap 2.4.22 with master/master syncrepl setup,
Apr 24 12:02:23 ldap01 slapd2.4[32233]: connection_close: conn=1005 sd=21
Apr 24 12:02:23 ldap01 slapd2.4[32233]: slapd shutdown: waiting for 59 operations/tasks to finish
Apr 24 12:02:34 ldap01 slapd2.4[26503]: bdb_db_open: database "": unclean shutdown detected; attempting recovery.
Apr 24 12:02:35 ldap01 slapd2.4[26503]: slapd starting
---------------------- Relevant Config ------------------------------------------------
TLSCertificateFile /etc/pki/tls/private/ldap.pem
TLSCertificateKeyFile /etc/pki/tls/private/ldap.pem
TLSCACertificateFile /etc/pki/tls/private/ldap.pem
serverID 001
database bdb
sizelimit 50000
cachesize 10000
checkpoint 256 5
syncrepl rid=001
bindmethod=simple
binddn="uid=xxxxrep,ou=xxxxxx,o=xxxxxx"
credentials=MyPassword
searchbase="o=xxxx"
schemachecking=on
sizelimit="unlimited"
timelimit="unlimited"
type=refreshAndPersist
interval=00:00:00:10
retry="5 5 60 +"
attrs="*,+"
mirrormode on
overlay syncprov
syncprov-checkpoint 100 10
syncprov-sessionlog 100
idletimeout 3600
threads 32