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ESXi 6.5 does not recognize Datastores that were recognized before with ESXi 5.x or 6.0 (2148265)

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  • VMFS datastores may be absent after upgrading to ESXi 6.5 despite path availability.

  • After upgrading an ESXi host version 6.5, one or more datastores may be absent.

  • The vmkernel log reports an error around UUIDs and device-registration failures:

    2017-06-02T17:12:54.076Z cpu23:65974)ScsiUid: 403: Existing device naa.6001f931059e80000113000200000000 already has uid vml.02000400006001f931059e80000113000200000000495345323430
    2017-06-02T17:12:54.076Z cpu23:65974)ScsiDevice: 4163: Failing registration of device 'naa.6001f931059e80000113000200000000'
    2017-06-02T17:12:54.076Z cpu23:65974)ScsiDevice: 4165: Failed to add legacy uid vml.02000400006001f931059e80000113000200000000495345323430 on path vmhba2:C0:T0:L4: Already exists
    2017-06-02T17:12:54.076Z cpu23:65974)WARNING: NMP: nmp_RegisterDevice:851: Registration of NMP device with primary uid 'naa.6001f931059e80000113000200000000' failed. Already exists

  • The storage path list will reveal multiple paths with “No associated device”

    # esxcli storage core path list

    UID: fc.20000025b5ab007c:20000025b5ac0049-fc.2000001f931059e8:2000001f931059e8-
    Runtime Name: vmhba2:C0:T0:L4
    Device: No associated device
    Device Display Name: No associated device
    Adapter: vmhba2
    Channel: 0
    Target: 0
    LUN: 4


This issue occurs when a storage array presents a device to an ESXi host with multiple LUN numbers. All devices have two identifiers used with ESXi – the device name (typically beginning with “naa. “, “eui. “, or “t10. “) and a “legacy identifier” generated by ESXi, beginning with “vml.” As the LUN number is part of the VML identifier, a conflict occurs when the same LUN is presented with multiple LUN numbers. In previous releases, ESXi would generate multiple legacy identifiers if this situation arose. This behavior changed in ESXi 6.5, and device registration will fail for devices presented with multiple LUN numbers.

  • This issue occurs because same device exists with two different IDs.

    Note : You can verify this with the following command:
esxcfg-scsidevs -l
  • Each device should only have one vml ID assigned (unless Pernix Data is being used). Example of problematic output: 
Device Type: Direct-Access
Size: 5145644 MB
Display Name: HP Fibre Channel Disk (naa.600c0ff000261b5db72dc75601000000)
Multipath Plugin: NMP
Console Device: /vmfs/devices/disks/naa.600c0ff000261b5db72dc75601000000
Devfs Path: /vmfs/devices/disks/naa.600c0ff000261b5db72dc75601000000
Vendor: HP Model: MSA 1040 SAN Revis: G210
SCSI Level: 6 Is Pseudo: false Status: on
Is RDM Capable: true Is Removable: false
Is Local: false Is SSD: false
Other Names:
VAAI Status: supported


This is an expected behavior with ESXi 6.5. LUN presentation must be consistent within each ESXi host for device registration to succeed. If you encounter this issue, adjust LUN presentation/mapping from the storage array to ensure that LUN numbers are presented consistently. Consistent LUN numbering is a storage best practice.

To resolve this issue, the presentation of LUNs must be fixed on the storage array in ESXi 6.5. Modify LUN presentation to ensure consistent numbering. The pre-6.5 behavior of permitting multiple legacy identifiers will be restored for most device types in a future patch or update release of ESXi 6.5.
Note: Previous versions of ESXi ignored this issue, but ESXi 6.5 will not access the device if this error is encountered.

Additional Information

  • To avoid service disruptions, always follow the published best practices from your storage vendor when making LUN presentation/mapping changes.

Prior to upgrading to ESXi 6.5, you can determine if you are exposed to this issue by examining device registrations from a pre-6.5 host. When examining the device registration, you should see only one VML identifier associated with each storage device. If you observe multiple VML identifiers, the device will fail registration after upgrade to ESXi 6.5.

 For example:

# esxcli storage core device list

Display Name: Fibre Channel Disk (naa.6001f931059e80000113000200000000)
Has Settable Display Name: true
Size: 10240
Device Type: Direct-Access
Multipath Plugin: NMP
Devfs Path: /vmfs/devices/disks/naa.6001f931059e80000113000200000000
[ … ]
Is VVOL PE: false
Is Offline: false
Is Perennially Reserved: false
Queue Full Sample Size: 0
Queue Full Threshold: 0
Thin Provisioning Status: unknown
Attached Filters:
VAAI Status: supported
Other UIDs: 

Note: Command output was reduced to improve clarity.

Alternatively, you may examine the short-form path list to list all paths to a device and check for differing LUN numbers.

For example:

# esxcfg-mpath -b

naa.6001f931059e80000113000200000000 : Fibre Channel Disk (naa.6001f931059e80000113000200000000)
vmhba2:C0:T0:L6 LUN:6 state:active fc Adapter: WWNN: 20:00:00:25:b5:ab:00:4f WWPN: 20:00:00:25:b5:ac:00:3f  Target: WWNN: 20:00:00:1f:93:10:59:e8 WWPN: 20:00:00:1f:93:10:59:e8
vmhba2:C0:T1:L6 LUN:6 state:active fc Adapter: WWNN: 20:00:00:25:b5:ab:00:4f WWPN: 20:00:00:25:b5:ac:00:3f  Target: WWNN: 20:00:00:1f:93:10:59:e8 WWPN: 20:00:00:1f:93:10:59:ed
vmhba1:C0:T3:L8 LUN:8 state:active fc Adapter: WWNN: 20:00:00:25:b5:ab:00:4f WWPN: 20:00:00:25:b5:ac:00:2f  Target: WWNN: 20:00:00:1f:93:10:59:e8 WWPN: 20:00:00:1f:93:10:59:e9
vmhba1:C0:T5:L8 LUN:8 state:active fc Adapter: WWNN: 20:00:00:25:b5:ab:00:4f WWPN: 20:00:00:25:b5:ac:00:2f  Target: WWNN: 20:00:00:1f:93:10:59:e8 WWPN: 20:00:00:1f:93:10:59:ec

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