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VMware ESXi host fails to format iSCSI LUN as VMFS datastores, despite devices being accessible

Last Updated:

Applies to

  • VMware vSphere ESXi 7.0.0
  • VMware vSphere ESXi 6.7
  • VMware vSphere ESXi 6.5
  • VMware vSphere ESXi 6.0


  • LUN is visible under Devices; however, it is not visible as a datastore
  • When trying to Add Storage, it gives a warning on formatting the LUN before proceeding
  • In /var/log/vmkwarning.log file, you may see similar entries:

YYYY-MM-DDT04:46:47.602Z cpu1:69214)WARNING: NMP: nmp_DeviceRequestFastDeviceProbe:237: NMP device "naa.600140593c9775cd3e97d449edb347dd" state in doubt; requested fast path state update...

<YYYY-MM-DD>T<time>.207Z cpu31:66363)WARNING: iscsi_vmk: iscsivmk_StopConnection: vmhba64:CH:0 T:1 CN:0: iSCSI connection is being marked "OFFLINE" (Event:4)</time>


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