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

24 Access Gateway Administrator’s Guide

53-1002156-01

Access Gateway mapping

• Make sure targets can be reached by the base device so that I/Os can resume if the mapped

device fails over and I/Os move over to the base PID.

• Reboot the server so that it initializes and uses configured device mapping.

Considerations for Access Gateway mapping

This section outlines considerations and limitations for Access Gateway mapping types.

Mapping priority

To avoid potential problems when both port and device mapping are implemented, AG uses the

following priority system when verifying policies to select the N_Port where a fabric login (FLOGI) is

routed. Access Gateway considers all available mappings in the following order until one can be

used.

1. Static device mapping to N_Port (if defined)

2. Device mapping to N_Port group (if defined)

For more information, refer to “Port Grouping policy” on page 35.

3. Automatic Device Load Balancing within a port group (if enabled)

For more information, refer to “Port Grouping policy” on page 35.

NOTE

Only NPIV devices can use device mapping and the automatic Device Load Balancing policy.

NOTE

Device Load Balancing policy is enabled per module rather than per port group.

4. Port mapping to an N_Port

5. Port mapping to an N_Port in a port group (if defined)

For more information, refer to “Port Grouping policy” on page 35.

Device mapping considerations

Consider the following points when using device mapping:

• If the N_Port is disabled, all devices that are mapped to it will be disabled. Depending on the

effective failover policy, the devices will be enabled on other N_Ports.

• Similar to port mappings, device mappings are affected by changes to underlying F_Ports. In

other words, if an F_Port needs to be taken offline, both the physical device and all virtual

nodes behind it will momentarily go offline.

• Once devices are mapped to an N_Port rather than an N_Port group, they cannot be

automatically rebalanced to another N_Port if an additional N_Port comes online.

• There can be cases where two NPIV devices logging in through the same F_Port are mapped to

two different N_Ports that are connected to two different fabrics. In this case, both NPIV

devices may be allocated the same PID by their respective fabrics. Once Access Gateway

detects this condition, it will disable that F_Port, and the event will be logged.