Failover on the backup installation

All processes on the backup installation point to the NCIM topology database on the primary installation. The NCIM topology database on the primary can be a standalone database or one configured for high availability.

Note: In previous Network Manager releases, users could include an NCIM topology database failover configuration by using NCIM replication (also referred to as NCIM topology database replication). The NCIM replication feature has been replaced by the high availability feature that is provided by the supported database:
  • If you have a Db2® database, you can use the High Availability Disaster Recovery (HADR) feature to set up failover for NCIM.
  • If you have an Oracle database, you can use the Real Application Clusters (RAC) feature to set up failover for NCIM.

The following figure shows an example Network Manager failover architecture, where the NCIM topology database is configured for high availability.

Figure 1. Example failover architecture with NCIM high availability
Example failover architecture with NCIM topology database backup

The following figure differs from the previous one in that the NCIM topology database is not configured for high availability.

Figure 2. Example failover architecture without NCIM high availability
Example failover architecture without NCIM topology database backup
Discovery
Although the Discovery engine (ncp_disco) and the SNMP Helper Server (ncp_d_helpserv) are run, the backup Network Manager server is not used for network discovery. When the backup domain is active, the topology does not change.
Event Gateway
When the backup domain is in standby mode, the Event Gateway does not enrich events on the ObjectServer. When the backup domain becomes active, the Event Gateway switches from the standby filter (StandbyEventFilter) to the incoming event filter (EventFilter).
NCIM
The backup ncp_model process does not update the NCIM topology database. However, the ncp_model process continues to provide topology services to processes such as the Event Gateway. The NCIM topology database that is used by the Network Views and the Hop View continues to hold the most current version of the network topology until the primary Network Manager server is restored and the system fails back.
Polling
When the backup domain is in standby mode, the Polling engine runs, but with polls suspended. When the backup domain becomes active, its ncp_poller process starts polling, and uses the SNMP target details and poll policies from the primary domain.
The ncp_poller process reads the SNMP configuration directly from its configuration file rather than relying on the discovery SNMP helper to read this file.
Virtual Domain
The backup Virtual Domain component opens a socket connection to the Virtual Domain of the primary Network Manager server. The topology data and any subsequent topology updates are copied from the ncp_model process on the primary server to the ncp_model process on the backup server.