556 A duplicate WWNN has been detected.
Explanation
The node has detected another device that has the same World Wide Node Name (WWNN) on the Fibre Channel network. A WWNN is 16 hexadecimal digits long. For the SAN Volume Controller system, the first 11 digits are 500507680C0 for DH8 and 500507680F0 for SV1. The last 5 digits of the WWNN are given in the additional data of the error. For more information, see "Service assistant interface." The Fibre Channel ports of the node are disabled to prevent disruption of the Fibre Channel network. One or both nodes with the same WWNN can show the error. Because of the way WWNNs are allocated, a device with a duplicate WWNN is normally another SAN Volume Controller node.
User response
Follow troubleshooting procedures to configure the WWNN of the node:
- Find the cluster node with the same WWNN as the node reporting the error. The WWNN for a cluster node can be found from the node Vital Product Data (VPD) or from the node details shown by the service assistant. . The node with the duplicate WWNN need not be part of the same cluster as the node reporting the error; it could be remote from the node reporting the error on a part of the fabric connected through an inter-switch link.
- If a cluster node with a duplicate WWNN is found, determine whether it, or the node reporting the error, has the incorrect WWNN. Also consider how the SAN is zoned when making your decision.
- Determine the correct WWNN for the node with the incorrect WWNN. If the correct WWNN cannot be determined contact your support representative for assistance.
- Use the service assistant to modify the incorrect WWNN. If it is the node showing the error that should be modified, this can safely be done immediately. If it is an active node that should be modified, use caution because the node will restart when the WWNN is changed. If this node is the only operational node in an I/O group, access to the volumes that it is managing will be lost. You should ensure that the host systems are in the correct state before you change the WWNN.
- If the node showing the error had the correct WWNN, it can be restarted, using the front panel power control button, after the node with the duplicate WWNN is updated.
- If you are unable to find a cluster node with the same WWNN as the node showing the error, use the SAN monitoring tools to determine whether there is another device on the SAN with the same WWNN. This device should not be using a WWNN assigned to a cluster, so you should follow the service procedures for the device to change its WWNN. Once the duplicate has been removed, restart the node.