troubleshooting NAS iSCSI device that's connected in devices but no datastore is mounted

[MOSOTI]

I've been trying to resolve this for a few hours now, I have a 4TB iSCSI LUN that is connect to ESXi and appears as a device but is not appearing as a datastore. The VM's on the missing datastore appear corrupt in the ESXi interface. 

I have added another LUN on the same NAS which mounts the new datastore just fine. Any assistance or advice is welcome. 

Running ESXi 6.7

[VM_Yamato]

Is this your environment？

• An ESXi host
• A Storage (iSCSI/NAS)
  • 1st LUN (4TB), it is connected as a device. And it has a VMFS with some VMs, but this is not mounted as a VMFS, so no VMs show, right?
  • 2nd LUN, this is a 2nd LUN on same NAS and it works correctly on same ESXi. 

Could you show us the your screenshot? (two storage devices on vSphere Client, error message if you get)

And did the 1st LUN(4TB, can't be seen as VMFS) work before? 

[MOSOTI]

Hi .. Yes, that's a good description. LUN was fully operable and stopped working over night. 
As described the partition appears intact, but I am not certain how to mount to try and read the data to recover any of the datastore.

Happy to share any information required.

[VM_Yamato · Accepted solution]

Understood and thanks share your environment.

So, the blue device's VMFS did work before, didn't it?

I guess your situation may be match this KB's case.

Troubleshooting LUNs detected as snapshot LUNs in vSphere (1011387)

[MOSOTI]

Thanks! Yes. The Blue 4TB was working previously. I will read up on the shared KB! Thankyou!

[MOSOTI]

@VM_Yamato Thank you so much!! This was exactly as described.

first time is a long time I have broken a sweat on vmware 🙂

Be safe.