Citrix ADC

Real-time synchronization between sites participating in GSLB

If you want to synchronize GSLB configuration across slave sites automatically when the commands are executed on master sites, you can now use the AutomaticConfigSync option to automatically synchronize the real-time GSLB configuration. You do not have to manually trigger the AutoSync option to synchornize the configuration.

Real-time synchronization is performed in the following manner:

  • The master site pushes its latest configuration file to all the slave sites.
  • Each slave site compares its own configuration with the latest configuration file sent by the master site. The slave site identifies the difference in configuration, and applies the delta configuration for its own site.
  • The slave site generates status logs at each step and copies them to a file at a specific location.
  • The master site pulls the status log files from the specified location.
  • The master site prepares a log file with logs combined from all the slave sites.
  • This combined log file is stored in /var/netscaler/gslb/periodic_sync.log file.

If you attempt to manually synchronize (with the sync gslb config command) a site while it is being autosynchronized, a “Sync in progress” error message appears. Autosynchronization cannot be triggered for a site that is in the process of being synchronized manually.


Starting with Citrix ADC 12.1 build 49.37, SNMP traps are generated when you synchronize the GSLB configuration. In real-time synchronization, the synchronization status in the first SNMP trap is captured as failure. You can ignore this status because a second SNMP trap is automatically generated immediately after the first trap with the actual synchronization status. However, if the synchronization failed in the second attempt also, SNMP trap is not generated because the synchronization status has not changed from the previous synchronization status.

For details on configuring Citrix ADC appliance to generate traps, see Configuring the Citrix ADC to generate SNMP traps.

Points to note

  • The consolidated log file related to real-time synchronization is stored in the /var/netscaler/gslb/periodic_sync.log directory.
  • The default configuration file is stored in the /var/netscaler/gslb_sync/ directory.
  • The master site uses the following directory structure:
    • The master site stores all its files in the /var/netscaler/gslb_sync/master directory.
    • The master site stores its configuration file that needs to be synced to the slave sites, in the /var/netscaler/gslb_sync/master/gslbconf/ directory.
    • The status files pulled from all the slave sites are stored in the /var/netscaler/gslb_sync/master/slavestatus/ directory.
  • The slave site uses the following directory structure:
    • The slave site picks up the latest configuration file to be applied from the /var/netscaler/gslb_sync/slave/gslbconf directory.
    • The slave site stores its status file in the /var/netscaler/gslb_sync/slave/gslbstatus directory.
  • In an admin partition setup, the same directory structure is maintained in the location: /var/partitions/partition name/netscaler/gslb_sync.

Best practices for using the real-time synchronization feature

  • It is recommended that all the Citrix ADC appliances participating as sites have the sameCitrix ADC software version.
  • To change the RPC node password, first change the password on the slave site and then on the master site.
  • Configure local GSLB sites on each site participating in GSLB.
  • Enable automaticConfigSync on one of the sites where the configuration is performed. This site eventually gets synchronized to other GSLB sites.
  • If there is a new configuration or changes are made to the existing configuration, make sure to check the status using the “show gslb syncStatus” command to confirm if the changes are synchronized across all sites or if there was any error.

To enable real-time synchronization by using the CLI

At the command prompt, type:

set gslb parameter –automaticConfigSync (ENABLED | DISABLED)


set gslb parameter –automaticConfigSync ENABLED

To enable real-time synchronization by using the GUI

  1. Navigate to Configuration > Traffic Management > GSLB > Change GSLB Settings.
  2. Select Automatic ConfigSync.

    Note: This option must be enabled only in the site where the configuration is performed.


For information on the following topics, see Manual synchronization between sites participating in GSLB.

  • Previewing GSLB synchronization
  • Debugging the commands triggered during synchronization process
Real-time synchronization between sites participating in GSLB