Considerations for access gateway mapping, Mapping priority – Dell POWEREDGE M1000E User Manual
Page 48
28
Access Gateway Administrator’s Guide
53-1002743-01
Access Gateway mapping
2
When this behavior occurs, the VM’s WWN will be properly logged in to the fabric. The WWN
appears in the output of ag --show and ag --wwnmapshow, as well as on the switch. The output from
the portperfshow command displays all traffic on the port to which the ESX server port is mapped
(base PID).
Configuring device mapping
To configure WWN mapping on VMware ESX systems, use the following steps.
1. Make sure that virtual world wide port names (VWWPN) of virtual machines (VMs) are mapped
to the correct port group (or N_Port). Map all VWWPNs to N_Ports to avoid confusion.
2. Make sure all VWWPNs are mapped for LUN access for array-based targets.
3. Make sure to include all VWWPNs in the zone configuration.
4. Reboot the VM.
5. Zone the server’s physical port to the storage device.
6. Check the traffic that originates from the virtual node PID (VN PID). If the configuration is
correct, traffic will flow from the VN PID.
For additional information on using device mapping for connecting VMware systems, refer to the
Technical Brief How to Configure NPIV on VMware ESX Server 3.5:
Failover and failback considerations
When using device mapping with VMware, the base device initiates PLOGI and PRLI to the target,
and then discovers the LUN. The virtual device also initiates a PLOGI and PRLI to the target, but
LUN discovery does not occur. Therefore, when the device-mapped port is toggled and failover or
failback takes place, traffic will resume from the base device. One of the following actions is
recommended when using device mapping with VMware:
•
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.
NOTE
Only NPIV devices can use device mapping and the automatic Device Load Balancing policy. Device
Load Balancing policy is enabled per module rather than per port group.