Gastarbajter

Fractional replication could be useful if you want to expose only a small set of the attributes to the wider audience. Apart from that it can significantly cut down the size of the database which makes it easier to fit in the memory of the 32-bit systems.

This article uses the existing supplier-consumer setup as a basis and converts it to the fractional replication mode. In the article which describes the supplier-consumer setup you would find the detailed explanation for the replication agreement attribute values to which we refer in this article under signs < and >.

On the consumer (the replica):

• disable the schema verification to avoid conflicts: (since we are replication only a subset of the attributes it could occur that we are not replicating the required attributes which would violate the schema for the given object class)

dn: cn=config
changetype: modify
replace: nsslapd-schemacheck
nsslapd-schemacheck: off

On the master:

• switch off the replication agreement on the master:

dn: cn=<agreement name>, cn=replica, cn=<suffix>, cn=mapping tree, cn=config
changetype: modify
replace: ds5AgreementEnable
ds5AgreementEnable: off

• modify the replication agreement to include the custom attribute set

dn: cn=include_<attr1>_<attr2>, cn=elements, cn=filtering service, cn=features,cn=config
changetype: add
objectClass: dsFilterSPFractionElement
objectClass: dsFilterSPConfigElement
objectClass: top
dsFilterSPType: fractional_include
dsFilterSPFractionAttr: <attr1>
dsFilterSPFractionAttr: <attr2>
dsFilterSPFractionAttr: <attrN>
cn: include_hzloc_<attr1>_<attr2>

dn: cn=set_include_<attr1>_<attr2>, cn=sets, cn=filtering service, cn=features,cn=config
changetype: add
objectClass: dsFilterSPConfigSet
objectClass: top
dsFilterSPConfigDefinition: (any && any && include_<attr1>_<attr2>)
dsFilterSPConfigEnable: on
cn: set_include_<attr1>_<attr2>

dn: cn=<agreement name>, cn=replica, cn=<suffix>, cn=mapping tree, cn=config
changetype: modify
add: ds5PartialReplConfiguration

ds5PartialReplConfiguration: set_include_<attr1>_<attr2>

The entry “cn=include_<attr1>_<attr2>, cn=elements, cn=filtering service, cn=features,cn=config” defines the attributes which are to be replicated. The list of attributes is held in the “dsFilterSPFractionAttr” attribute. The name of this entry is automatically generated by the Administration Console as include_<attribute 1>_<attribute 2> but it can any other name. The same applies for the set_include_ entry.

• enable the replication agreement:

dn: cn=<agreement name>, cn=replica, cn=<suffix>, cn=mapping tree, cn=config
changetype: modify
replace: ds5AgreementEnable
ds5AgreementEnable: on

• initialize the replica from the master:

dn: cn=<agreement name>, cn=replica, cn=<suffix>, cn=mapping tree, cn=config
changetype: modify
replace: nsDS5BeginReplicaRefresh
nsDS5BeginReplicaRefresh: start