ESXi storage rescan not completing after storage array relocation

Products

• VMware vSphere ESXi

Issue/Introduction

• Storage rescan tasks on ESXi hosts in a cluster time out or fail to complete.

• The issue occurs following a physical relocation or maintenance of a storage array connected to the hosts.
• Some hosts in the cluster may operate normally, while others which were connected to the relocated array fail to see the storage or complete the rescan.

Environment

VMware vSphere ESXi 8.x

VMware vSphere ESXi 9.x

Cause

This issue can be caused by physical connectivity errors introduced during the storage array relocation, specifically cross-site cabling.

If the storage array is incorrectly cabled to the fabric or the hosts, the ESXi storage stack cannot establish valid paths, leading to timeouts during the discovery (rescan) phase. 

Resolution

To resolve this issue, perform a thorough audit of the physical and logical storage connectivity:

Verify Physical Cabling:

• Ensure all fiber or network cables are connected to the correct ports on both the storage array and the FC/Ethernet switches.
• Verify that no cross-site or cross-fabric cabling errors were made during the relocation. 

Check Switch Zoning/Connectivity

• Log in to your FC switches and verify that the host WWNs and storage front-end ports are logged in and visible.
• Ensure that the zoning configuration matches the new physical locations of the array ports.

Confirm Array Presentation:

• Verify on the storage array side that the hosts are correctly exported/masked to the appropriate target ports.

Perform Storage Rescan:

• Once connectivity is verified and corrected, perform a storage rescan on the affected ESXi hosts using the vSphere Client or the command line.
• For CLI instructions; Performing a rescan of the storage on an ESXi host

Note: Incorrect cabling can lead to All Paths Down (APD) or Permanent Device Loss (PDL) conditions if existing datastores are expected on the moved array. Ensure all VMs are migrated or powered off before performing physical moves.