Operating Considerations

In a high availability deployment, it is important that only one Controller is the active Controller at one time. Only the database processes should be running on the secondary so that it can maintain a replicated copy of the primary database.

The Controller app server process on the HA secondary can remain off until needed. Having two active primary Controllers is likely to lead to data inconsistency between the HA pair.

When a failover occurs, the secondary app server must be started or restarted (if it is already running, which clears the cache).

Note:

To benefit from increased replication setup speeds, your server will need access to network resources capable of some hundreds of MB per second. By specifying replication setup parallelism, you can radically reduce setup times.

For example, if a single rsync is using only one-fifth of the available network capacity, you can achieve maximum throughput for setup by appending -P r5 to end of the replicate.sh command. If this level of network traffic interferes with the ongoing Controller operation, you should monitor and adjust this setting.

  • If you are using HA Toolkit version 3.54 and later, append -P r5 to end of the replicate.sh command
  • If you are using the HA module with Enterprise Console (version 4.5.17 and later), you must add the --args numberThreadForRsync=5 to the CLI
  • From the Enterprise Console UI, select Number of parallel rsync threads for incremental or finalize (depending on what stage you are performing)