Partial Replication

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Partial replication is a replication feature that replicates only the specified entries and a subset of attributes for the specified entries within a subtree. You can use the information provided here to know more about partial replication.

The entries and attributes that are to be replicated are specified by the LDAP administrator. Using partial replication, an administrator can enhance the replication bandwidth depending on the deployment requirements. For instance, an administrator may choose the entries of the object class person with cn, sn, and userPassword attributes to be replicated and description attribute not to be replicated.

The attributes that are to be replicated are specified using a replication filter. A replication filter may be associated with a particular replication agreement and will be based on object classes. A set of attributes pertaining to an object class constitutes a replication filter. The list of attributes selected for an object class can either be a part of an inclusion list or an exclusion list. An inclusion list is list of attributes that will be selected for replication while an exclusion list is list of attributes that will not be selected for replication. However, the administrator must ensure that the MUST attributes of an object class should not be excluded. If MUST attributes are excluded for an object class, then the replication of entries containing that object class might fail, which will set the replication state as retrying. This might block the replication for that particular replication agreement. For example, consider the following setting:
dn: cn=replicationfilter1,cn=localhost
objectclass: ibm-replicationfilter
ibm-replicationFilterattr: (objectclass=person):!(sn)
ibm-replicationFilterattr: (objectclass=*):(*)
In this case, if the filter ibm-replicationFilterattr: (objectclass=person):!(sn) is given, then entries with object class as person will fail to replicate and block the replication because sn is a MUST attribute for the person object class.
The following attributes are always replicated, irrespective of their presence in the exclusion list
  • Object class attributes of an entry
  • Naming attribute
  • All operational attributes
For information about known limitations of partial replication, see General Information, Known Limitations and General Troubleshooting in the Troubleshooting and support section of the IBM® Security Verify Directory documentation.

The partial replication feature can be managed using the web administration tool or from the command line.