Failover Process | High Availability | Teradata Data Mover - Failover Process - Teradata Data Mover

Teradata® Data Mover User Guide

Product
Teradata Data Mover
Release Number
16.20
Published
November 2021
Language
English (United States)
Last Update
2021-11-04
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wph1512683331242.ditamap
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B035-4101
lifecycle
previous
Product Category
Analytical Ecosystem

The dmcluster service script is used to run various commands on the cluster. The dmcluster service script can be found in /opt/teradata/client/nn.nn/datamover/failover/, where nn.nn is the major and minor version numbers of Data Mover, for example 16.10. After the cluster configuration completes using dmcluster config, all active components are started in active mode. If the active daemon, agents or sync service are running, they are stopped and restarted in active mode. All standby components are stopped and the sync service on the remote sync server is started in standby mode. The monitoring service starts monitoring the active components by making SSH connection to the active component servers at regular intervals to check if the services are up and running. If the active Data Mover daemon, active repository, active ActiveMQ, or all agents used by the active daemon are down, a failover sequence is initiated on the standby daemon server. The failover sequence shuts down the daemon, agents, ActiveMQ, and sync service on the active servers and starts the daemon, agents, ActiveMQ, and sync service in active mode on the standby server. An attempt is made to the start the old active sync service in standby mode.

Once the failover sequence completes, the monitoring service shifts to the standby monitoring server and begins monitoring the new active components. If the monitoring service finds a running daemon or ActiveMQ process on the standby server, it automatically shuts it down to prevent two services from being active at the same time.

Running the dmcluster status command should at this point should show the following:
  • The Data Mover daemon is NOT RUNNING on local.daemon.host
  • The Data Mover sync service is RUNNING as standby on local.repository.host
  • The Data Mover agents are NOT RUNNING on the hosts specified for local.agents.host
  • The monitoring service is NOT RUNNING on local.monitor.host
  • The Data Mover daemon is RUNNING on remote.daemon.host
  • The Data Mover sync service is RUNNING as active on remote.repository.host
  • The Data Mover agents are RUNNING on the hosts specified for remote.agents.host (unless any agents are shared by active and standby daemon)
  • The monitoring service is RUNNING on remote.monitor.host
  • The ActiveMQ is RUNNING on remote.daemon.host
  • The ActiveMQ is NOT RUNNING on local.daemon.host

The dmFailover.log provides more information on the failover sequence.

Refer the Teradata® Data Mover Installation, Configuration, and Upgrade Guide for Customers, B035-4102 to know more about how to configure a failover. This section talks about all the components used in a failover.