TMS zl Management and Configuration Guide ST.1.1.100430

8-5
High Availability
Overview
Caution Be careful to configure and reboot cluster members in the appropriate order.
You must configure HA on the intended master first and reboot it, so that it is
the first member of the cluster. If the intended master is not configured and
rebooted first, the intended participant will become the actual master, and you
will lose the master’s configuration settings.
For example, suppose that you already have one TMS zl Module installed and
configured in its host switch, and you want to install a second, unconfigured
module for HA and you take the following actions:
1. Configure the second module for HA and reboot it
2. Configure the original module for HA and reboot it.
If you configure the modules in this order, the unconfigured module will boot
first with the HA setting and assume the role of the master. When the original,
configured module comes online, it detects the cluster master and reboots
using the cluster master’s startup-config, which has no configuration settings.
All of the original module’s settings will be lost.
Linking Inter-Chassis Clusters
An inter-chassis cluster consists of cluster members that are physically
located in different switch chassis. When connecting the two chassis, follow
these guidelines:
■ There should be at least one Layer 2 link and preferably redundant links,
between the two switch chassis.
■ If you use redundant links, enable the switches’ Multiple Spanning-Tree
Protocol (MSTP) or Rapid Spanning-Tree Protocol (RSTP) functionality
to prevent a loop.
■ The switch ports that connect the host switches should be tagged mem-
bers of the HA VLAN.
■ All TMS VLANs must be configured on both host switches.
■ It is highly recommended that other network devices not be placed
between the switch chassis that contain the cluster members to reduce
the risk of link failure.