Technical data

BLADE OS 5.1 Application Guide
BMD00136, November 2009 Chapter 14: High Availability
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Manual Monitor Configuration
Figure 29 is a simple example of Layer 2 Failover. One G8000 is the primary, and the other is used
as a backup. In this example, all ports on the primary switch belong to a single trunk group, with
Layer 2 Failover enabled, and Failover Limit set to 2. If two or fewer links in trigger 1 remain
active, the switch temporarily disables all control ports. This action causes a failover event on
Server 1 and Server 2.
Figure 29 Basic Layer 2 Failover
Setting the Failover Limit
The failover limit lets you specify the minimum number of operational links required within each
trigger before the trigger initiates a failover event. For example, if the limit is two, a failover event
occurs when the number of operational links in the trigger is two or fewer. When you set the limit to
zero, the switch triggers a failover event only when no links in the trigger are operational.
Manually Monitoring Port Links
The Manual Monitor allows you to configure a set of ports and/or trunks to monitor for link failures
(a monitor list), and another set of ports and/or trunks to disable when the trigger limit is reached (a
control list). When the switch detects a link failure on the monitor list, it automatically disables the
items in control list. When server ports are disabled, the corresponding server’s network adapter can
detect the disabled link, and trigger a network-adapter failover to another port or trunk on the
switch, or another switch.
The switch automatically enables the control list items when the monitor list items return to service.
Trigger 1
Trigger 1
Primary
Switch
Backup
Switch
Server 1
Server 2
NIC 1
NIC 2
NIC 1
NIC 2
Internet
Enterprise
Routing Switches