When you install a server, you can add it to an existing topology, cloning the server's configuration. Topology settings are designed to operate without additional configuration. If required, some settings can be adjusted to fit the needs of the environment.
Server configuration settings
Configuration settings for the topology are configured in the global configuration and in the config file handler backend. They are topology settings, but they are unique to each server and are not mirrored. Settings must be kept the same on all servers.
The global configuration object contains a single topology setting,
force-as-master-for-mirrored-data. This should be set to
true on only one of the servers in the topology, and is used only if
the topology cannot determine a primary because most of the servers are not available. A
server with this setting enabled is assigned the role of primary if no suitable primary
can be determined.
The config file handler backend defines three topology mirrored-subtree settings:
- Specifies the frequency at which the server polls its topology peers to identify any changes warranting a new primary selection. A lower value ensures a faster failover, but it also causes more traffic among the peers. The default value is 5 seconds. If no suitable primary is found, the polling frequency adjusts to 100 milliseconds until a new primary is selected.
- Specifies the maximum length of time to wait for an entry update operation, such as add, delete, modify or modify-dn, to be applied by the primary on all of the servers in the topology. The default is 10 seconds, but updates can take up to twice as long if primary selection is in progress at the time the update operation is received.
- Specifies the maximum length of time in milliseconds to wait for search operations to complete. The default is 10 seconds.
Topology metadata is stored under the cn=topology,cn=config subtree and cluster data is stored under the cn=cluster,cn=config subtree. The only setting that can be changed is the cluster name.