Device naa. with a VMFS partition is marked perennially reserved in the vmkernel log

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• Powering on a virtual machine fails.
• A virtual machine fails which leads to becoming in an orphaned state.
• A virtual machine backup job fails.
• In the /var/log/vmkernel.log file of the ESXi host where the virtual machine is running, you see entries similar to:
  
  Device naa.xxxxxxxxxxxx with a VMFS partition is marked perennially reserved. This is not supported and may lead to data loss.

Environment

VMware vSphere ESXi 7.0.0
VMware vSphere ESXi 6.7
VMware vSphere ESXi 6.5

Cause

This issue occurs due to:

• An VMFS backed datastore has been incorrectly set as perennially reserved = true.
• An RDM LUN that was previously used within a MSCS cluster setup has been repurposed as a VMFS datastore and the flag has not been unset.

Resolution

To resolve this issue, the perennially reserved flag must be removed on each ESXi host that has visibility to the affected LUN(s).

To remove the perennially reserved flag:

1. Run this command to verify that the device is perennially reserved:
   
   esxcli storage core device list -d naa.id
    
2. In the output of this command, search for the entry Is Perennially Reserved: true.
   
   Example:
   
   esxcli storage core device list -d naa.600508b1001030364537433543300700
   
   
    
3. Run this command to remove the flag:
   
   esxcli storage core device setconfig -d naa.id --perennially-reserved=false
    
4. Run this command again and confirm that the device is no longer perennially reserved:
   
   esxcli storage core device list -d naa.id

Additional Information

You could execute this command to list out all the devices along with their reservation status:

esxcli storage core device list | grep -E 'Display|Perennially'| grep -v "Has Settable Display Name"

Note: The KB above is not applicable to Clustered VMDK. VMware recommends settings perennially reserved flag on Clustered VMDK. Refer to the KB 1016106 for more details.

Impact/Risks:
VMware strongly recommends against setting a VMFS backed datastore to perennially reserved as this could lead to a lot of complications with the functioning of the VMs that are part of this datastore and in the long run could potentially also lead to data loss/corruption.