Failover Usage Notes | High Availability | Teradata Data Mover - Usage Notes - Teradata Data Mover

Teradata® Data Mover User Guide - 20.01

Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
Lake
VMware
Product
Teradata Data Mover
Release Number
20.01
Published
November 2023
Language
English (United States)
Last Update
2023-12-05
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Product Category
Analytical Ecosystem

Use host names or IP addresses as values in failover.properties. The following table describes what happens in certain scenarios when using the automatic failover feature:

Scenario Result
The default password for dmuser has been changed on any of the servers specified in failover.properties. SSH setup fails, which prevents the active-standby components from starting correctly.
Invalid host names are specified in failover.properties. The SSH setup fails.
Config is run as a user other than ROOT. The SSH setup fails.
The dm.rest.endpoint is not modified in commandline.properties. The command line is not able to connect to a standby REST server when the active REST server becomes unavailable.
The broker.url is not modified in daemon.properties and agent.properties. The daemon and agent are not able to connect to a standby JMS broker when the active JMS broker becomes unavailable.
The sync.ismaster value in sync.properties is not set correctly on both active and standby sync servers. The sync monitor service does not start correctly.
The active sync monitor become unavailable when the cluster is running in active mode. Check the synchronization and Postgres logs on the primary daemon server to diagnose the root cause of the issue. See Fixing Sync Service with High Availability.
Both daemon servers become unavailable after failover monitoring has been enabled. The monitoring service detects the primary daemon server failure and initiates a failover sequence on the secondary daemon server. If it is unable to connect to the secondary daemon server, it exits and the components need to be reconfigured and restarted using the dmcluster switchback command from the primary daemon server once the servers are up.
The primary daemon becomes unavailable and a failover has been initiated. The daemon is restarted again using the dmdaemon service script. The monitoring service notices two daemons running and stops the daemon on the primary server. To properly restore the unavailable daemon, use the dmcluser switchback command on the primary server.

For more information, see Switching Back to the Primary Daemon.

The secondary daemon is started using the dmdaemon service script when the primary daemon is still running. The monitoring service notices two daemons running and stops the daemon on the secondary server. Components on the secondary servers cannot be started when the primary server is running in active mode. If a permanent change of servers is necessary, reconfigure the Data Mover cluster using the dmcluster config command on the server to become the new primary server.
The JMS broker on the primary daemon server becomes unavailable. Failover occurs if ActiveMQ cannot be started by the failover service after a multiple attempts.
ActiveMQ on the secondary daemon starts. Failover stops the service automatically. Components on the secondary servers cannot be started when the primary server is running in active mode. If a permanent change of servers is necessary, reconfigure the Data Mover cluster using the dmcluster config command on the server to become the new primary server.