Troubleshooting
Problem
Some modern Fibre Channel (FC) attached storage subsystems incorporate N-Port ID Virtualization (NPIV) to facilitate controller failover feature by using an integrated limited function FC switch.
These storage subsystems respond to the Virtual I/O Server (VIOS) lsnports command when attached directly to the VIOS partition's FC adapters but do not provide a suitable or supported configuration for use with VIOS NPIV clients.
Symptom
- Multipath failover problems resulting from HBA (host-side adapter) failures.
- Inability to get all NPIV client virtual adapters logged-in to the switch or storage simultaneously
Cause
PowerVM attempts to prevent mapping of virtual FC adapters to physical FC connections that do not support NPIV.
PowerVM VIOS relies on responses to the lsnports command from the FC devices attached to the adapters to determine whether they are NPIV-capable.
PowerVM expects physical FC adapters to be connected to fully functional SAN switches.
Since these storage subsystems have their own NPIV capabilities their response to lsnports is misleading and allows inappropriate mapping to be performed on the VIOS partition.
Environment
PowerVM / VIOS 2.*,3.1
Host-side NPIV clients
Direct-attached FC storage subsystems with NPIV controller failover feature
Diagnosing The Problem
Check for direct attach FC storage.
Refer to the product documentation for the storage subsystem for any statements about this scenario.
EG:
"The system supports configurations that use N_port ID virtualization (NPIV) in the host bus adapter when they are connected to a SAN switch. However, these configurations are not supported when they are directly attached to the Fibre Channel ports on the system."
For IBM storage, check the IBM System Storage Interoperation Center (SSIC) site for your configuration.
Note the following options are mutually exclusive:
- Connection Protocol = Fibre Channel - Virtual (NPIV)
- SAN or Networking = Direct Attach (Adapter attached directly to storage
Resolving The Problem
Incorporate suitable SAN switches.
Related Information
Document Location
Worldwide
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Document Information
Modified date:
11 February 2020
UID
ibm11571469