ESXi HBA storage adapter paths show 0 after I/O module replacement

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms

After replacing an I/O module on an ESXi host, the following symptoms are observed:

• Host Bus Adapter (HBA) storage adapter paths show as 0.

• The vmhba adapters appear as Online in the vSphere Client, but no datastores are visible.

• Storage rescans do not restore connectivity.

• Host reboots fail to resolve the path visibility issue.

• vmkernel.log contains errors such as: port initialization not complete.

  2026-03-26T03:54:38.172Z cpu14:2100100 opID=14ad1731) vmw_ahci[000000xx5] :< 1> scsiDiscover:port initialization not complete

  2026-03-26T03:54:38.172Z cpu14:2100100 opID=14ad1731) vmw_ahci[000000xx5] :< 2> scsiDiscover:port initialization not complete

Environment

• VMware ESXi vSphere 7.x

• VMware ESXi vSphere 8.x

• Fibre Channel (FC) Storage Area Network (SAN)

• Cisco UCS

Cause

Replacement of the I/O module (IOM/FEX) in a Cisco UCS environment led to changes in service profile connectivity behavior, as the system re-discovered and re-integrated the new module, impacting existing interface pinning and fabric paths.

Resolution

To restore connectivity and align with the hardware vendor to perform the following steps:

1. Physical Layer Audit

Verify the physical connections to the replaced hardware:

• Perform a cable audit to ensure FC cabling is connected to the correct peer ports.
• Swap cabling if necessary to match the documented Cisco or storage vendor specifications for the specific chassis.
• Ensure that Fabric IDs are synchronized across the I/O modules.

2. Fabric and Zoning Verification

Verify that the SAN fabric recognizes the host:

• Check the Fibre Channel switch for "No Alias name" errors or zoning mismatches.
• Update Zoning Aliases to reflect any hardware changes, ensuring the new I/O module is a recognized member of the zone.

3. Check the service profile from the vendor side as the system needs to re-discover and re-integrated the new module.