Brocade Access Gateway Administrator's Guide (53-1000605-01, October 2007)

6 Access Gateway Administrator’s Guide

53-1000605-01

Failover and Failback policies

When a port is configured as an N_Port, the Failover policy is enabled by default. If a primary

N_Port goes offline because a cable is removed or any other offline event, the F_Ports that are

mapped to the N_Port are disabled. If a Preferred Secondary N_Port is set for any of the F_Ports,

and if those N_Ports are online, these F_Ports will be failed over to their respective Preferred

Secondary N_Port, and then re-enabled. Otherwise, if a Preferred Secondary N_Port is set, but is

not online, those F_Ports are disabled.

Alternatively, if a Preferred Secondary N_Port is not set for any of these F_Ports, these F_Ports

fail-over to other online N_Ports belonging to the same N_Port group, and then re-enables. The

FLOGI and FDISC requests are forwarded from F_Ports through the new N_Port. Failover of F_Ports

to new N_Ports generates a RASLOG message. If multiple N_Ports are available as candidates for

failover, Access Gateway selects one or more N_Ports so that the F_Ports are evenly balanced

across all these N_Ports.

Cold Failover

All F_Ports for an N_Port that goes offline are failed over to other N_Ports. However, if the N_Port

fails to come online after the switch comes online, it triggers cold failover of its F_Ports. If any of

these F_Ports have the Preferred Secondary N_Port set, and if the Preferred Secondary N_Port is

online, those F_Ports fail over to the Preferred Secondary N_Port during cold failover. If a Preferred

Secondary N_Port is set for any of these F_Ports and the Preferred N-Port is not online, then those

F_Ports are disabled. If the Preferred Secondary N_Port is not set for any of these F_Ports, these

F_Ports failover to any N_Ports on the switch so that the F_Ports are evenly balanced across all the

N_Ports belonging to the same N_Port group.

NOTE

Access Gateway incorporates a number of Path Failover and Failback policies to ensure maximum

up time for the servers.

Port initialization

To ensure that all hosts are brought online when Brocade Access Gateway starts up, the ports are

initialized in the following manner:

1. All N_Ports are initialized. During N_Port initialization all the F_Ports are disabled (kept offline).

The ports are enabled or disabled as follows:

• Enabled (online) if the port receives a fabric login event and is connected to an F_Port of

an edge switch that supports NPIV (N_Port ID virtualization).

• Disabled (offline) if the port is not connected to a fabric or is connected to a fabric port

that does not support NPIV.

2. All F_Ports mapped to online N_Ports are enabled.

3. F_Ports mapped to an offline N_Port with the failover policy enabled fail over to an online

N_Port.

4. The host logs in to the fabric as follows: