When an entry is modified, a change record describing the LDAP operation that was performed is recorded in the changelog.

The changelog size is maintained with two attributes, nsslapd-changelogmaxageor nsslapd-changelogmaxentries. These attributes trim the old changelogs to keep the changelog size reasonable.

6.1.1.5 Replication agreement

Directory Servers use replication agreements to define replication. A replication agreement describes replication between a single supplier and a single consumer. The agreement is configured on the supplier server. It identifies:

•The database to replicate.

•The consumer server to which the data is pushed.

•The times that replication can occur.

•The DN that the supplier server must use to bind (called the supplier bind DN).

•How the connection is secured (TLS/SSL, Start TLS, client authentication, SASL, or simple authentication).

•Any attributes that will not be replicated (see “Replicated selected attributes with fractional replication”).

6.1.2Data consistency

Consistency refers to how closely the contents of replicated databases match each other at a given point in time. Part of the configuration for replication between servers is to schedule updates. The supplier server always determines when consumer servers need to be updated and initiates replication.

Directory Server offers the option of keeping replicas always synchronized or of scheduling updates for a particular time of day or day in the week.

The advantage of keeping replicas constantly synchronized is that it provides better data consistency. The cost is the network traffic resulting from the frequent update operations. This solution is the best option when:

•There is a reliable, high-speed connection between servers.

•The client requests serviced by the directory service are mainly search, read, and compare operations, with relatively few update operations.

If it is all right to a lower level of data consistency, choose the frequency of updates that best suits the use patterns of the network or lowers the affect on network traffic. There are several situations where having scheduled updates instead of constant updates is the best solution:

•There are unreliable or intermittently available network connections.

•The client requests serviced by the directory service are mainly update operations.

•Communication costs have to be lowered.

In the case of multi-master replication, the replicas on each supplier are said to be loosely consistent, because at any given time, there can be differences in the data stored on each supplier. This is true, even if the replicas are constantly synchronized, for two reasons:

•There is a latency in the propagation of update operations between suppliers.

•The supplier that serviced the update operation does not wait for the second supplier to validate it before returning an "operation successful" message to the client.

6.2Common replication scenarios

Decide how the updates flow from server to server and how the servers interact when propagating updates. There are the four basic scenarios and a few strategies for deciding the method

6.2 Common replication scenarios 75

Page 74 Page 76
Page 75
Image 75
HP UX Direry Server manual Common replication scenarios, Data consistency, Replication agreement
Page 74 Page 76

UX Direry Server specifications

HP UX Directory Server is a robust and scalable solution designed for managing directory information within enterprise networks. Developed by Hewlett-Packard (HP), this server offers an extensive set of features tailored to meet the needs of organizations that require an efficient way to store, manage, and retrieve identity and access data.

One of the key features of HP UX Directory Server is its ability to handle large directories with significant volumes of data. Built on a highly optimized architecture, it provides excellent performance and can support millions of entries without sacrificing speed or reliability. This capability makes it an ideal choice for large-scale deployments in enterprises that require high availability and responsiveness.

In addition to its scalability, HP UX Directory Server supports a wide range of protocols, including LDAP (Lightweight Directory Access Protocol), which ensures seamless integration with diverse applications and systems across various platforms. The server maintains standards compliance, which facilitates interoperability and simplifies administration tasks.

Security is a top priority for HP UX Directory Server, offering an array of features to protect sensitive information. It supports secure data transmission via TLS/SSL protocols, ensuring encrypted communication between clients and servers. Advanced access controls allow administrators to define fine-grained permissions, helping to safeguard directory data against unauthorized access.

Another salient feature of HP UX Directory Server is its replication capabilities. The server can replicate directory data across multiple instances, ensuring data consistency and availability in distributed environments. This feature is essential for businesses operating across different geographical locations or requiring failover solutions for disaster recovery.

HP UX Directory Server also comes equipped with tools for data management, including an intuitive administration console for configuring and monitoring the server. Additionally, it offers customizable schema capabilities, enabling organizations to tailor the directory structure to fit their specific needs.

Integration with existing identity management solutions is streamlined through connectors and APIs, allowing organizations to extend their directory services and enhance user experience.

In summary, HP UX Directory Server is a powerful directory management solution that combines scalability, security, and integration flexibility. Its support for industry standards, advanced replication, and comprehensive administrative tools makes it an essential asset for organizations seeking to manage identity and access efficiently. By leveraging this technology, businesses can improve their operational efficiency and ensure a secure and organized approach to directory management.
Top Page Image Contents