Unable to mount a VMFS volume to an ESXi Host

Products

• VMware vSphere ESXi

Issue/Introduction

• When trying to mount a datastore to an ESXi Host you encounter the following problem.

  'An unresolved VMFS volume with signature naa.################################:# has been detected on disk'.

• The option to mount the datastore with 'Assign new signature' and or 'Keep existing signature' are both greyed-out. The only available option is to 'Format the disk'.

Reason for not being able to mount the datastore: duplicate extents found or some extents missing.

Validation:

• Running the command 'esxcfg-volume -l' gives the following output.

  VMFS UUID/label: ########-########-####-########/datastorename
  Can mount: No (duplicate extents found)
  Can resignature: No (duplicate extents found)
  Extent name: eui.################################:1 range: 0 - ########(MB)
  Extent name: eui.################################:1 range: 0 - ########(MB)

  or

  VMFS UUID/label: ########-########-####-########/datastorename
  Can mount: No (some extents missing)
  Can resignature: No (some extents missing)
  Extent name: naa.################################:1    range: 0 - 292607 (MB)

Environment

VMware vSphere ESXi 7.x
VMware vSphere ESXi 8.x

Cause

While running 'esxcfg-volume -l' if the reason for not being able to mount the datastore is:

• duplicate extents found - There are 2 snapshots of the same datastore presented to the Host.
• some extents missing - The original datastore is a multiextent datastore, and the snapshot lun of the datastore needs access of all the snapshot luns for the same datastore.

Resolution

• If the reason for not being able to mount the datastore is 'duplicate extents found':

1. 1. Detach one of the duplicate snapshot LUNs presented to the Host
   2. Re-signature the remaining snapshot LUN presented to the host by running the below command.

      esxcli storage vmfs snapshot resignature -u "########-########-####-############"

• If the reason for not being able to mount the datastore is 'some extents missing':
  
  
  1. Validate whether the host has access to all the multi-extent snapshot luns for the same datastore.
  2. Re-signature the snapshot LUNs presented to the host  by running the below command.
     

     esxcli storage vmfs snapshot resignature -u "########-########-####-############"

Additional Information

• Troubleshooting LUNs detected as snapshot LUNs in vSphere
• VMFSボリュームをESXiホストにマウントできません