Basic replication
Once the z/OS LDAP server is installed and configured, users can access the directory, add entries, delete entries, or perform search operations to retrieve particular sets of information.
Replication is a process which keeps multiple directories in sync. Through replication, a change made to one directory is propagated to one or more additional directories. In effect, a change to one directory shows up on multiple different directories.
There are several benefits realized through replication. The single greatest benefit is providing a means of faster searches. Instead of having all search requests directed at a single server, the search requests can be spread among several different servers. This improves the response time for the request completion.
Additionally, the replica provides a backup to the replicating server. Even if the replicating server crashes, or is unreadable, the replica can still fulfill search requests, and provide access to the data.
- In peer to peer replication, each LDAP peer server is a read/write
server. Updates processed on one peer server are replicated to all
the other peer servers. Peer servers are read/write to all users.Note: The basic replication support for peer to peer replication is provided for failover support purposes. With basic peer to peer replication, there is no support for resolving simultaneous updates on multiple peer servers, which can cause a failure of replication. As a result, updates should be targeted to one peer server at a time.
- In basic read-only replication, a single read/write LDAP server
(the master) replicates the updates it processes to a set of read-only
replica servers.
- Master
- All changes to the directory are made to the master server. The master server is then responsible for propagating the changes to all other directories. It is important to note that while there can be multiple directories representing the same information, only one of those directories can be the master.
- Read-only replica
- Each of the additional servers which contain a directory replica. These replica directories are identical to the master directory. These servers are read-only to all users and only accept updates from their master server.
A basic replication network can contain both peer replica servers and read-only replica servers. In this case, each peer server must act as a master to each read-only replica (in addition to being a peer to all the peer servers), so that updates that occur on any peer server are replicated to all the other peer and read-only replicas in the network.
Basic replication is supported when the servers involved are running in single-server or in multi-server mode. See Configuring the operational mode for more information about server operating modes.
In z/OS LDAP, basic replication is supported in the LDBM and TDBM backends but is not supported in the SDBM or GDBM backends or the schema entry.