I have setup two ldap servers for authentication and access control in a multi-master configuration. I am concerned about the number of contextcsn entries that are supposed to be present in each database. Right now there are two servers participating in the multi-master configuration. From my understanding, there should be one contextCSN entry per database per host. My cn=config database has two contextCSN entries as I would expect. One for each syncrepl rid configured. My bdb database only has one contextCSN entry though, with an rid of just “000”. (my rid’s are 001, 002, 101, and 102)

Replication seems to work fine on both databases. I can write to either one and the changes are replicated over immediately. I am just curious about this discrepancy in the number of contextCSN entries. Could someone confirm the number of contextCSN entries per database and if it should match the number of hosts participating in the multi-master replication?  Here are some relevant settings for the replication:

dn: cn=config

olcServerID: 1 ldap://<server1>

olcServerID: 2 ldap://<server2>

#######################

# module{0}, config

dn: cn=module{0},cn=config

objectClass: olcModuleList

cn: module{0}

olcModulePath: /usr/lib64/openldap2.4

olcModuleLoad: {0}syncprov.la

#######################

# {0}config, config

dn: olcDatabase={0}config,cn=config

olcSyncrepl: {0}rid=001 provider=ldap://<server1> binddn="cn=Ma

 nager,cn=config" bindmethod=simple credentials=<password> searchbase="cn=config

 " type=refreshAndPersist retry="5 500 5 +" timeout=1 starttls=yes

olcSyncrepl: {1}rid=002 provider=ldap://<server2> binddn="cn=Ma

 nager,cn=config" bindmethod=simple credentials=<password> searchbase="cn=config

 " type=refreshAndPersist retry="5 500 5 +" timeout=1 starttls=yes

olcMirrorMode: TRUE

#######################

# {0}syncprov, {0}config, config

dn: olcOverlay={0}syncprov,olcDatabase={0}config,cn=config

objectClass: olcOverlayConfig

objectClass: olcSyncProvConfig

olcOverlay: {0}syncprov

#######################

# {1}bdb, config

dn: olcDatabase={1}bdb,cn=config

olcSyncrepl: {0}rid=101 provider=ldap://<server1> binddn="cn=Ma

 nager,dc=mgcorp,dc=net" bindmethod=simple credentials=<password> searchbase="dc

 =mgcorp,dc=net" type=refreshAndPersist interval=00:00:00:10 retry="5 500 5 +"

  timeout=1 starttls=yes

olcSyncrepl: {1}rid=102 provider=ldap://<server2> binddn="cn=Ma

 nager,dc=mgcorp,dc=net" bindmethod=simple credentials=<password> searchbase="dc

 =mgcorp,dc=net" type=refreshAndPersist interval=00:00:00:10 retry="5 500 5 +"

  timeout=1 starttls=yes

olcMirrorMode: TRUE

##############################

Here are the results of searches for contextCSN in cn=config and dc=mgcorp,dc=net:

ldapsearch -x -W -s base -D "cn=Manager,cn=config" -h "<server2>" -b "cn=config" contextCSN

contextCSN: 20101110214932.998233Z#000000#000#000000

contextCSN: 20101028121213.444193Z#000000#001#000000

ldapsearch -x -W -s base -D "cn=Manager,dc=mgcorp,dc=net" -h "<server2>" -b "dc=mgcorp,dc=net" contextCSN

contextCSN: 20101110213409.736943Z#000000#000#000000