Unable to discover or mount iscsi LUNs and datastores though the targets are updated in static discovery

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• iSCSI datastores are visible and mounted on some hosts in a cluster but missing on others.

• The target LUNs do not appear in the Devices list even after performing a rescan of the storage adapter and devices.

• A vmkping from the affected ESXi host to the iSCSI target IP addresses results in 100% packet loss.

  vmkping -I vmk# -s 1472 -d 10.#.#.#
PING 10.#.#.# (10.#.#.#): 1472 data bytes

  --- 10.#.#.# ping statistics ---
3 packets transmitted, 0 packets received, 100% packet loss

• The MTU configured is uniform and there is no mismatch

• The /var/run/log/vobd.log file on the affected host shows network communication or connectivity failures.

  2026-01-08T07:00:00.479Z In(14) vobd[2097717]: [iscsiCorrelator] 1012308076493us: [esx.problem.storage.iscsi.target.connect.error] Login to ISCSI target iqn.1992####################### on vmhba64 @ vmk# failed. The ISCSI initiator could not establish a network connection to the target.
2026-01-08T07:00:00.479Z In(14) vobd[2097717]: The event ([esx.problem.storage.iscsi.target.connect.error] Login to iSCSI target iqn.1992####################### on vmhba64 @ vmk# failed. The iSCSI initiator could not establish a network connection to the target.) was sent immediately to hostd;
2026-01-08T07:00:09.246Z In(14) vobd[2097717]: [iscsiCorrelator] 1012336916836us: [vob.iscsi. target.connect.error] vmhba64 @ vmk# failed to login to iqn.1992####################### because of a network connection failure.

Environment

VMware ESXi 8.x

VMware ESX 9.x

Cause

A configuration mismatch between the host and the physical network switch. Specifically, the required VLAN tag is not configured on the switch port for the non-working host, preventing network traffic from routing correctly.

Cause Validation:

• On working hosts, vmkping to the iSCSI targets is successful with 0% loss. On non-working hosts, the same test fails completely.

• From the vmkernel interface configuration, it is observed that on both working and non-working ESXi hosts, the vmkernel interface has VLAN configured.

  For example, in the below screenshot, vmk3 interface is used for iscsi connectivity and there is a VLAN tagging.

  

• On the working ESXi hosts, the physical adapters do not have any specific VLAN tagging or restriction. However, on the non working ESXi host, there is VLAN tagging at the physical switch and this does not allow the traffic through VLAN1

  Non working host:

  

• Also, on reviewing the VLAN stats, on the problematic ESXi host, there are no packets received for the VLAN1

  esxcli network nic vlan stats get -n vmnic#
VLAN 1
Packets received: 0
Packets sent: 3
  
  

Resolution

Engage your networking team and ensure that the physical network adapters and the connected switch ports are configured to allow traffic for the specific VLAN ID used by the iSCSI VMkernel interfaces.