Live Partition Mobility (LPM) and Simplified Remote Restart (RR) are powerful and advanced virtualization and high availability capabilities on IBM Power Systems. However, in complex SAN environments, selecting the right Fibre Channel (FC) ports during these operations can be challenging. This is especially true when multiple Virtual I/O Server (VIOS) partitions and FC adapters are involved and can access the SAN through multiple FC ports

To address this, HMC introduced FC Port Group Labels—a simple but effective way to guide HMC during LPM and RR operations.

This blog explains:

·       What FC port group labels are

·       How to assign, remove, and query FC Port Labels

·       How labels influence LPM and RR behaviour

·       How to control label-matching behaviour using override settings

Why FC Port Group Labels Matter

In many customer environments, FC ports are not interchangeable. Some ports may be connected to production storage, others to test environments, some ports reserved for future growth or different SAN fabrics. Without additional context, HMC may select any compatible FC port during LPM or RR.

FC port group labels solve this problem by allowing administrators to logically tag FC ports and guide HMC’s selection logic.

For example:

·       Label production FC ports as FC.PROD

·       Label Reserved FC ports as FC.RESERVED

·       Label test FC ports as FC.TEST

During LPM or RR, HMC can then attempt to match ports with the same label on the destination system.

Assigning Group Labels to FC Ports

FC port group labels are assigned at the VIOS FC port level using the labelvios command line interface (CLI).

Example: Assigning a Label

labelvios -m system   -o s -l FC.PROD -i "resource=fcport,vios_names=vios1,port_name=fcs0"

Key Points

·       The VIOS must be running with an active RMC connection

·       VIOS must be running VIOS 3.1.4.0 or later

·       Label names can be up to 16 characters

·       Naming rules are the same as user-defined partition names

·       The FC port name must exist on the VIOS

Once assigned, the label becomes part of the FC port’s metadata and is used for future LPM and RR operations.

Removing an FC Port Group Label

If a label is no longer required, it can be safely removed without disrupting I/O.

Example: Removing a Label

labelvios -m system   -o r -i "resource=fcport,vios_names=vios1,port_name=fcs0"

Removing a label simply removes the logical association—it does not impact active workloads or existing SAN connectivity.

Querying FC Port Group Labels

To view FC port labels across VIOS partitions, use the lslabelvios command.

Example: Query All FC Ports

lslabelvios -m system   -r fcport

Sample Output

name=vios1,lpar_id=1,port_name=fcs0,port_label=FC.PROD

name=vios1,lpar_id=1,port_name=fcs1,port_label=

name=vios2,lpar_id=2,port_name=fcs0,port_label=FC.RESERVED

name=vios2,lpar_id=2,port_name=fcs1,port_label=FC.TEST

This makes it easy to validate label consistency across VIOS partitions before performing LPM or RR.

How FC Port Labels Are Used During LPM and RR

When launching an LPM or Simplified Remote Restart operation, you can control how strictly HMC enforces FC port label matching by using a new override parameter.

Override Parameter

--viosfcportlabel 1|2

What the Values Mean

1 – Required

·       FC port labels must match between source and destination VIOS partitions

·       All source VIOS partitions must have support FC port labels

·       If no matching destination VIOS is found, the operation fails

This option is ideal for environments where SAN consistency is critical.

2 – If possible

·       HMC attempts to match labels

·       If no match is found, HMC may select FC ports with different or no labels

·       Warning messages may be generated

This option provides greater flexibility, especially in mixed or down-level environments.

How FC Port Labels Are Used During LPM GUI

A new “Vios FC port labels” drop-down has been added to the Migration Information screen. It lets you choose how strictly FC port labels should be enforced during migration. You can leave it as No Selection (the default), which uses the source system’s default behavior, or explicitly choose If possible or Required based on how strict you want the matching to be.

Setting a Default Label Matching Policy at system level

If no override is specified during LPM or RR, HMC falls back to the default FC port label override setting on the managed system.

Example: Set Default Policy

labelvios -m system   -o s -r default -i "fc_port_label_override=1"

Available Values

·       1 – required

·       2 – if possible

This allows administrators to enforce consistent behaviour without requiring users to specify overrides for every operation.

Cross-HMC Considerations

In cross-HMC scenarios, version compatibility matters:

·       If the source HMC is pre-1030, the target HMC always uses if possible

·       If the source HMC uses required but the destination HMC is pre-1030, the operation fails

These safeguards ensure backward compatibility while preventing unsafe migrations.

Querying the Default Setting

To check the default FC port label override on a managed system:

lslabelvios -m system  -r default

To retrieve only the FC port override value:

lslabelvios -m system  -r default -F fc_port_label_override

Best Practices

·       Use meaningful and consistent labels (for example, FC.PROD, FC.DR.B, FC.RESERVED, FC.TEST)

·       Label FC ports symmetrically across VIOS partitions

·       Use required mode in production environments with strict SAN separation

·       Validate labels before performing LPM or RR

·       Document label usage as part of SAN design standards

Visual representation of FC Port labels

Summary

FC Port Group Labels provide a lightweight yet powerful mechanism to improve storage port selection during LPM and Simplified Remote Restart. By adding intent to FC ports, administrators gain greater predictability, control, and confidence when performing mobility operations in complex SAN environments.

If you are already using LPM or RR, enabling FC port group labels is a small change that can deliver big operational benefits.

Contacting the PowerVM Team

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Authors

Malapati Raghavendra

Devesh Kumar Singh