Recording WWPN changes of replaced host HBAs

You can use the command-line interface (CLI) to record a change to a defined host object.

Sometimes it is necessary to replace the host-bus adapter (HBA) that connects the host to the SAN. You must inform the system of the new worldwide port names (WWPNs) that the replacement HBA contains.

Ensure that your switch is zoned correctly.

To inform the system of a change to a defined host object, complete the following steps.

Enter the following CLI command to list the candidate HBA ports.
```
lsfcportcandidate
```
or
```
lssasportcandidate
```
You see a list of the HBA ports that are available for addition to host objects. One or more of these HBA ports corresponds with one or more WWPNs that belong to the new HBA port.
Locate the host object that corresponds with the host in which you replaced the HBA. The following CLI command lists all the defined host objects:
```
lshost
```
Enter the following CLI command to list the WWPNs that are currently assigned to the host object.
```
lshost hostobjectname
```
Where hostobjectname is the name of the host object.
Enter the following CLI command to add the new ports to the existing host object.
```
addhostport -fcwwpn one or more existing port names
 separated by :hostobjectname/ID
```
Where one or more existing port names separated by : is the WWPNs that are currently assigned to the host object and hostobjectname/ID is the name or ID of the host object.
Enter the following CLI command to remove the old ports from the host object.
```
rmhostport -fcwwpn one or more existing port names
 separated by :hostobjectname/ID
```
Where one or more existing WWPNs separated by a colon (:) are the WWPNs that are currently assigned to the host object and hostobjectname/ID is the name or ID of the host object.
Note: If the following conditions are met when volume protection is enabled for the system, the deletion of the specified host port fails.
- It is the last active port on the host.
- It is mapped to any volume that received I/O within the specified volume protection interval.
If volume protection is enabled, and the host port being deleted is the last port for a host, which is mapped to any volume that received I/O within the defined volume protection time period, then the command fails. If multiple hosts are mapped to the same active volume, the system deletes the port if the host is offline.

Any mappings that exist between the host object and the volumes are automatically applied to the new WWPNs Therefore, the host sees the volumes as the same SCSI LUNs as before.

See the IBMMultipath Subsystem Device Driver User's Guideor the documentation that is provided with your multipathing driver for additional information about dynamic reconfiguration.