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1
Failover policy
FIGURE 4
Failover policy
The Brocade Access Gateway N_Port failover policy allows hosts to automatically remap to an
online N_Port if the N_Port they are connected to goes offline. The failover policy evenly distributes
the F_Ports that are mapped to an offline N_Port among all the online N_Ports. The failover policy
is a parameter of each N_Port. By default, the failover policy is enabled for all N_Ports.
The following sequence describes how a failover event occurs:
1. An N_Port goes offline.
2. All F_Ports mapped to that N_Port are disabled.
3. If the N_Port failover policy is enabled, the disabled F_Ports are remapped to an online N_Port.
4. The F_Port is re-enabled on the new N_Port.
5. The host establishes a new connection with the fabric.
COLD FAILOVER
F_Ports that are mapped to an N_Port, that goes offline, will fail over to other N_Ports that are
connected to the same fabric. In the case that an N_Port fails to come online, even once, its
F_Ports will be distributed evenly across all active N_Ports regardless of their attached fabric. Since
Fabric OS 5.3.0 does not support multiple fabrics, this should be not be a likely scenario. Cold
failover is determined for an N_Port under the following condition:
•
If at a later time the "dead" N_Port comes online, the failback policy will be enforced for all F_Ports
mapped to the N_Port.
6
After ports are initialized, Access Gateway becomes logically transparent to the host and
the fabric, as shown in
a
e
Host log in request
The F_Ports are evenly distributed among the remaining online N_Ports.
After the switch comes online, the N_Port fails to successfully login to the enterprise fabric
within 10 seconds. This can happen due to any of the following reasons:
-
N_Port is not connected to the enterprise fabric
-
NPIV is not enabled on fabric port to which a N_Port is connected
-
Fabric Login request from N_Port is rejected by enterprise fabric with a reason other than
"LS_LOGICAL_BUSY"
Figure
4.
c
b
d
Access Gateway Administrator's Guide
53-1000633-01
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