Brocade Access Gateway Administrator's Guide Supporting Fabric OS v7.0.0 (53-1002156-01, April 2011)

Access Gateway Administrator’s Guide 45

53-1002156-01

Failover

NOTE

All the device data must be persistent in case of a reboot. During a reboot, the tables will be dumped

to the persistent_NPIV_config file.

Persistent ALPA policy considerations

The Persistent ALPA policy is not supported in the following situations:

• When AG N_Ports are connected to the shared ports of 48-port Director blades.

• Cisco fabrics. Enable Persistent FCID mode on the connecting Cisco switch to achieve the

same functionality.

• Persistent ALPA configuration will not change to the default when the configDefault command

is used, but will retain the previous configuration.

Failover

The Access Gateway Failover policy ensures maximum uptime for the servers. When a port is

configured as an N_Port, the Failover policy is enabled by default and is enforced during power-up.

The Failover policy allows hosts and targets to automatically remap to another online N_Port if the

primary N-Port goes offline.

NOTE

For port mapping, the Failover policy must be enabled on an N_Port for failover to occur. For device

mapping, if a device is mapped to an N_Port in a port group, the device will always reconnect to the

least-loaded online N_Port in the group (or secondary N_Port in the group if configured) if the

primary N_Port goes offline. This occurs regardless of whether the Failover policy is enabled or

disabled for the primary N_Port.

Failover with port mapping

The Failover policy allows F_Ports to automatically remap to an online N_Port if the primary N_Port

goes offline. If multiple N_Ports are available for failover, the Failover policy evenly distributes the

F_Ports to available N_Ports belonging to the same N_Port group. If no other N_Port is available,

failover does not occur and the F_Ports mapped to the primary N_Port go offline as well.

AG provides an option to specify a secondary failover N_Port for an F_Port.

Failover configurations in Access Gateway

The following sequence describes how a failover event occurs:

• An N_Port goes offline.

• All F_Ports mapped to that N_Port are temporarily disabled.

• If the Failover policy is enabled on an offline N_Port, the F_Ports mapped to it will be

distributed among available online N_Ports. If a secondary N_Port is defined for any of these

F_Ports, these F_Ports will be mapped to those N_Ports. If the Port Grouping policy is enabled,

then the F_Ports only fail over to N_Ports that belong to the same port group as the originally

offline N_Port.