vSphere HA VM restarts due to iSCSI storage path flapping and All Paths Down (APD) in VMware vSphere ESXi

Products

• VMware vSphere ESXi

Issue/Introduction

• Virtual Machines (VMs) undergo unplanned restarts triggered by vSphere HA.
• ESXi hosts report intermittent connectivity or flapping on storage paths.
• In /var/log/vmkernel.log, the following entries are observed:
  • WARNING: NMP: nmp_DeviceRequestFastDeviceProbe: NMP device "naa.################" state in doubt; requested fast path state update...
  • Device or filesystem with identifier [naa.################] has entered the All Paths Down state.
  • Abort command issued for the affected iSCSI adapter (e.g., vmhba64).
  • WARNING: iscsi_vmk: iscsivmk_TaskMgmtIssue:637: vmhba64:C#: T:# L:# : Task mgmt "Abort Task" with itt=0x2efb4fe3 (refITT=0x2efb4f79) timed out.
• vSphere HA reports VM Component Protection (VMCP) events due to datastore inaccessibility.

Environment

VMware vSphere ESXi 7.x, 8.x

Cause

This issue occurs when an ESXi host loses path redundancy and the remaining active paths experience intermittent connectivity (flapping). When all paths to a storage device become unavailable, the host enters an All Paths Down (APD) state. If vSphere HA is configured with VM Component Protection (VMCP), it will initiate a restart of the affected VMs on healthy hosts in the cluster.

Resolution

1. Verify the current status of storage paths by running the following command on the affected ESXi host: esxcli storage core path list
2. Inspect physical hardware and fabric components, including network switches, cables, and GBICs, for signs of intermittent failure.
3. Review storage array logs to identify any port-side errors or controller failovers that match the timing of the path flapping.
4. Ensure that iSCSI Port Binding is correctly configured to maintain session redundancy across different physical NICs and fabrics.
5. If fabric maintenance is planned, ensure the alternate fabric is stable and verifying redundancy before proceeding.