Configuring SAN communication with LPM

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If a PowerHA® SystemMirror® cluster is configured and deployed with storage area network (SAN) communication, you might have to complete a few extra steps before and after you use Live Partition Mobility (LPM). SAN communication is not required for various cluster operations.

About this task

PowerHA SystemMirror uses network-based communication for typical cluster management. If your cluster environment is configured for SAN communications and a critical network failure occurs, the cluster functions switch from network-based communication to SAN communication. If SAN communications fail or are not available, the cluster functions use repository disk-based health management.

You can perform LPM on a PowerHA SystemMirror LPAR that is configured with SAN communication. You can use LPM when network communication is configured for SAN communication. However, when you use LPM the SAN communication is not automatically migrated to the destination system. You must configure SAN communication on the destination system before you use LPM.

Perform LPM operations on an LPAR only when the network communication is healthy from the LPAR across the cluster.

To use LPM on a node in the cluster that is configured with SAN communication, complete the following steps:

Procedure

  1. Verify that the TME flag for the FC adapters inside VIOS is set to yes.
    Note: If you change the TME flag, yout might need to reboot the system because the change requires the adapter to be reinitialized. Therefore, access to the storage disk through the adapter is disrupted. You must proactively plan for this disruption and enable the TME flag before you start the LPM process.
  2. Start the LPM process. You can ignore warning messages on the target side for SAN communication. Specifically, you can ignore any warning messages about the missing VLAN port 3358.
    Note: On the destination VIOS system, enter the lsdev -Ct storfwork command to verify whether a sfwcommX device is already identified as a VLAN storage framework communication.
  3. On the destination system, reestablish SAN communication between VIOS and the client LPAR. To configure SAN communication on the destination system, you must configure the virtual LAN adapters that are related to SAN communication for the VLAN 3358 adapter on VIOS. To reestablish VLAN communication between the client LPAR and SAN communication module, use the cfgmgr command from VIOS.
    Note: The time taken to reestablish communication for the SAN communication routing tables depends on the number of hops or elements in the SAN fabric between the host systems. The time taken to reestablish communication does not affect cluster operations.