2. The Directory Server Access Control Model
3. Understanding the Directory Server Schema
4. Directory Server Index Databases
5. Understanding Directory Server Plug-Ins
6. Directory Server Replication
Overview of the Directory Server Replication Architecture
Basic Replication Architecture
Directory Server Change Processing
Historical Information and Conflict Resolution
What is a Replication Conflict?
Purging Historical Information
Schema Replication Architecture
Replication Status Definitions
Full Update Status and Bad Generation ID Status
Safe Read Mode and Replication Groups
Assured Replication Connection Algorithm
Assured Replication and Replication Status
Assured Replication Monitoring
Fractional Data Set Identification
Fractional Replication Filtering
Fractional Replication and Local Operations
How the External Change Log Works
Porting Applications that Rely on Other Change Logs
Differences Between the ECL and the LDAP Change Log Draft
Additional Differences Between the ECL and the Sun DSEE Retro Change Log
API for Compatibility With the LDAP Change Log Draft and the Sun DSEE Retro Change Log
Limitations of the Compability API
Despite efforts to keep servers in sync, directory servers can begin to show incoherent data. Typically, this occurs in the following circumstances:
A disk error taints the stored data
A memory error leads to an error in processing data
A software bug leads to bad data or missing changes
In such cases, tracking and replaying changes is not sufficient to synchronize the incoherent data.
An automatic repair mechanism is provided, which leverages historical information inside entries to determine what the coherent data should be. The replication mechanism then repairs the data on directory servers where the data is bad or missing. The auto repair mechanism is implemented as an LDAP application, and runs on the hosts that run replication servers.
The auto repair application can run in different modes. Depending on the mode in which it is run, the auto repair application performs the following tasks:
Repairs inconsistencies manifested as an error when the server was replaying modifications
Repairs inconsistencies detected by the administrator
Periodically scans directory entries to detect and repair inconsistencies
Note - In the current directory server release, the auto repair mechanism must be run manually. For more information, see Detecting and Resolving Replication Inconsistencies in Sun OpenDS Standard Edition 2.2 Administration Guide.