Advice for LDAP Application Developers

Understanding and Deploying LDAP Directory Services > 10. Replication Design > Why Replicate?

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Why Replicate?

When you replicate directory content, you increase the reliability and performance of your directory service. Let's examine these two benefits and how they are achieved.

By making the directory data available in more than one location, you improve the reliability of your directory service. In the event that a single server fails, your directory clients and directory-enabled application programs could contact a different server for their directory service .Figure 10.1 illustrates how a client can use this redundancy to obtain service from a replica in the event of a server failure.

Figure 10.1 Increasing reliability through redundancy.

When you replicate directory content, you also make your directory more impervious to outages as a result of network failures. In Figure 10.2, the directory-enabled application running on the LAN at the branch office can continue to function even if the network link between the branch office and company headquarters is down. Of course, the directory content on the replicated server may not be entirely up-to-date, but for the vast majority of applications this is entirely acceptable. When the network connection between the offices is restored, Server B will once again be synchronized with Server A, eliminating any temporary differences.

Figure 10.2 Replicating to minimize the impact of a network failure.

The situation in Figure 10.2 also has the benefit that replicas can be located close to the users and applications that need them. This improves performance because there are fewer network nodes between the LDAP clients and the directory data.

Thus, when you replicate directory content, you can also improve the performance of your directory. Your directory can be made to handle more directory client requests by distributing the load across more servers. Figure 10.3 illustrates distribution of client load across multiple replicas.

Figure 10.3 Distributing directory client load.


Understanding and Deploying LDAP Directory Services,  2002 New Riders Publishing
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Index terms contained in this section

directories
          replication
                    avoiding outages
                    improving performance
                    improving reliability
outages
          avoiding through replication
performance
          improving through replication
reliability
          improving through replication
replication
          avoiding outages
          improving performance
          improving reliability

2002, O'Reilly & Associates, Inc.



Understanding and Deploying LDAP Directory Services
Understanding and Deploying LDAP Directory Services (2nd Edition)
ISBN: 0672323168
EAN: 2147483647
Year: 1997
Pages: 245

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