HP 8/40 Brocade Access Gateway Administrator's Guide v6.3.0 (53-1001345-01, Ju - Page 49

Persistent ALPA Policy 3 • If an N_Port is added to a port group or deleted from a port group and login balancing is enabled or disabled for the port group, the N_Port maintains its original failover or failback setting. If an N_Port is deleted from a port group, it automatically gets added to port group 0. • When specifying a preferred secondary N_Port for a port group, the N_Port must be from the same group. If you specify an N_Port as a preferred secondary N_Port and it already belongs to another port group, the operation fails. Therefore, it is recommended to form groups before defining the preferred secondary path. • If the PG policy is disabled while a switch in AG mode is online, all the defined port groups are deleted, but the F_Port-to-N_Port mapping remains unchanged. Before disabling the PG policy, you should save the configuration using the configupload command in case you might need this configuration again. • If N_Ports connected to unrelated fabrics are grouped together, N_Port failover within a port group can cause the F_Ports to connect to a different fabric and the F_Ports may lose connectivity to the targets they were connected to before the failover, thus causing I/O disruption as shown in Figure 7 on page 24. Ensure that the port group mode is set to Managed Fabric Name Monitoring (MFNM) mode. This monitors the port group to detect connection to multiple fabrics and disables failover of the N-ports in the port group. For more information on MFNM, refer to "Enabling Managed Fabric Name Monitoring mode" on page 28. Upgrade and downgrade considerations for the Port Grouping policy Downgrading to Fabric OS v6.2.0 or earlier is supported. Note the following considerations when upgrading and downgrading from Fabric OS v6.3.0 to Fabric OS v6.2.0 and earlier: • When upgrading to Fabric OS v6.3.0, the PG policy that was enforced in Fabric OS v6.2.0 continues to be enforced in Fabric OS v6.3.0 and the port groups are retained. You should save the configuration file using the configupload command in case you might need this configuration again. • If you upgrade from Fabric OS 5.3.0 to 6.0 or higher, you will not see any change in device behavior where the Port Grouping policy is enabled by default. Persistent ALPA Policy This policy is meant for host systems with proprietary operating systems that cannot handle different ALPA addresses across login sessions. The persistent ALPA policy for switches in Access Gateway mode lets you configure the AG module so that the host gets the same ALPA when the host logs out and logs in from the same F_Port. The benefit of this feature is that it will ensure a host has the same ALPA on the F_ports though the host power cycle. You can also achieve the same behavior and benefit by setting the same policy in the main (core) fabric. When this feature is enabled, AG will request the same ALPA from the core fabric. However, depending on the Fabric, this request may be denied or a different ALPA may be generated. In this case two options are available. • In "Flexible" mode the AG will only log an event that it did not receive the same ALPA from the core fabric and continues the operation. Access Gateway Administrator's Guide 29 53-1001345-01