Configuring synchronization

Last published : Sep 24, 2026
Synchronization is a process of duplicating the configuration of the primary node on the secondary node. The purpose of synchronization is to ensure that there’s no loss of configuration information between the primary and the secondary nodes, regardless of the number of failovers that occur. Synchronization uses TCP port 3008 or 3010.
Synchronization is triggered when one of the following conditions is met:
  • The secondary node in an HA setup comes up after a restart.
  • The primary node becomes secondary after a failover.
Automatic synchronization is enabled by default. You can also force synchronization.
Note:
  • Command propagation is disabled during HA synchronization to prevent any conflicting command settings, which can lead to command propagation failure.
  • During an HA synchronization, the secondary node runs the clear ns config command to clear the existing configuration and load the new configuration pulled from the primary node. However, the clear configuration does not remove the default static route configured in the secondary node. If this default static route points to an incorrect gateway, it might result in downtime of the services.
  • We recommend exchanging the heartbeat messages on a native VLAN or in the presence of syncvlan.
Related information

Disabling or enabling synchronization

Automatic HA synchronization is enabled by default on each node in an HA pair. You can enable or disable it on either node.

To disable or enable automatic synchronization by using the CLI

At the command prompt, type:
  • set HA node -haSync DISABLED
  • set HA node -haSync ENABLED

To disable or enable synchronization by using the GUI

  1. Navigate to System > High Availability.
  2. Under HA Synchronization, select the Secondary node will fetch the configuration from Primary checkbox to enable synchronization.

Forcing the secondary node to synchronize with the primary node

In addition to automatic synchronization, the NetScaler supports forced synchronization. You can force the synchronization from either the primary or the secondary node. When you force synchronization from the secondary node, it starts synchronizing its configuration with the primary node.
However, if synchronization is already in progress, forced synchronization fails and the system displays a warning. Forced synchronization also fails in any of the following circumstances:
  • You force synchronization on a standalone system.
  • The secondary node is disabled.
  • HA synchronization is disabled on the secondary node.

To force synchronization by using the CLI

At the command prompt, type:
force HA sync

To force synchronization by using the GUI

  1. Navigate to System > High Availability.
  2. On the Nodes tab, in the Action list, click Force Synchronization.