Show TOC

Removing a Backup HostLocate this document in the navigation structure


You can remove a backup host from a distributed system. You may want to do this if you used the host for test purposes and no longer need it in the distributed system.


  1. Start the TREX admin tool on any host in the distributed system.
  2. Go to the Index Landscapewindow. Check the column <light><host_name>:<index_server_port> for the host that you want to remove.
    1. Check which indexes the host is assigned to as the backup index server.

      If you remove this host, TREX automatically removes these assignments. The affected indexes then no longer have a backup index server. If you want indexing to be highly available, you need to assign these indexes to another backup index server.

    2. Check whether the backup index server is currently active.

      This is displayed in the column using the entry +backup. You should not remove the host if the backup index server is active. If you remove the host anyway, the system does not switch automatically to using the master index server. The master index server is only assigned to the affected indexes when it is next started.

    3. Check whether the host is assigned to any indexes as the master index server.

      If this is the case, you have to assign another master index server to the indexes before removing the host.

    4. Check whether the host is assigned to any indexes as the slave index server.

      If you remove the host, TREX removes these assignments automatically. You have to assign these indexes to another slave index server too.

    See also:Changing Index Assignments

  3. Go to the QueueLandscape window. Check the same things for the queues as you just checked for the indexes.

    See also:Changing Queue Assignments

  4. If you are sure that you want to remove the host, go to the Landscape Configuration window.
  5. Select the host in the Hosts table and then choose Remove Host.
  6. Check the configuration. If the check does not find any errors, activate the configuration using Deploy.


The TREX instance is still installed on the removed backup host. The host may still contain configuration data with information on the distributed system. However, since these configuration files are not consistent, the TREX instance on this host will normally not start any longer. You should therefore deinstall this TREX instance.