ESXi 8.0 Upgrade Causes iSCSI Datastore Connectivity Loss Due to Subnet Mismatch
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ESXi 8.0 Upgrade Causes iSCSI Datastore Connectivity Loss Due to Subnet Mismatch

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Article ID: 451828

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

  • An issue occurs where iSCSI datastores and storage targets become unreachable from a VMware ESXi host, resulting in datastore connectivity failure.
  • Affected hosts may show datastores as "Inaccessible" or display a capacity of "0" within the vSphere Client.
  • Attempts to troubleshoot network connectivity via vmkping from the dedicated iSCSI VMkernel interface fail with the error: Network unreachable.

Environment

VMware vSphere ESXi

Cause

Misconfiguration of static or dynamic iSCSI target IP addresses on the host software iSCSI adapter, causing outgoing initiator traffic from VMkernel adapters  to target an unroutable subnet.

Resolution

To restore connectivity, verify and correct the static discovery target IP configuration.

Prerequisites:

  • Ensure you have established management access to the host.
  • Record the current static target configuration for reference.

Steps:

  1. Identify the current iSCSI VMkernel IP and Subnet: Open the ESXi shell or use the vSphere Client to verify the configured IP and subnet mask for your iSCSI VMkernel adapters


      esxcfg-vmknic -l



  2. Verify the configured iSCSI Target IP: In the vSphere Client, navigate to Hosts and Clusters > Configure > Storage > Storage Adapters.
    • Select the iSCSI Software Adapter.
    • Navigate to the Static Discovery tab.
    • Compare the iSCSI Server (Target) IP address against the storage network requirements. Ensure the target IP corresponds to the valid, routable subnet of the iSCSI VMkernel adapters.
  3. Correct the Target IP Address:
    • If an incorrect IP address (e.g., <incorrect_subnet_ip>) is found, select the entry and click Remove.
    • Click Add to create a new entry with the correct target IP address (e.g., <correct_target_ip>).
  4. Perform Storage Rescan:
    • Under Storage Adapters, select the iSCSI Software Adapter.
    • Click Rescan Adapter.

     5. Validate Connectivity: Test connectivity from the iSCSI VMkernel interface to the correct target IP


     vmkping -I <vmk_interface> <correct_target_ip>


If successful, the datastores should automatically mount and display the correct capacity.

Additional Information

For further guidance on iSCSI troubleshooting, refer to the following documentation:

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