Error: Failed to create swap file - Module Monitoring Loop Power On Failed on vSAN cluster

Products

• VMware vCenter Server

Issue/Introduction

• A virtual machine fails to start on a vSAN cluster with the following error messages:
  • Module Monitoring Loop Power On Failed
  • Failed to start the virtual machine
  • Failed to create swap file '/vmfs/volumes/vsan:####/####.vswp': Failure
• vMotion of the VM will also fail. 

Environment

• VMware vSAN (All Versions)
• VMware vCenter Server Appliance

Cause

• This issue occurs when the vSAN cluster is assigned a license that does not support the features being used.
  • An Evaluation License in use is either expired or is been replaced by a vSAN license that fails to furnish all the features.
  • Other reason is if the hosts in vSAN cluster don't reflect the licensed features in use as per the license applied to the cluster.
• When a vSAN license expires, the cluster enters a restricted compliance mode that prevents the creation or mounting of new vSAN storage objects, including virtual machine swap (.vswp) files required for power-on.

Steps to verify the vSAN licenses:

• If vCenter is accessible,
  • click on the hamburger menu in the upper left, select Administration > Licensing > Licenses and check the vSAN licenses applied to the cluster.
• If vCenter is not accessible,
  • check to see if the hosts reflect the appropriate licensed features per the vSAN license applied to the cluster on each host by running below command. 

    • vsish -e get /config/VSAN/strOpts/LicensedFeatures

• For Example, 
  • Non-Working scenario:
    • vsish -e get /config/VSAN/strOpts/LicensedFeatures
      • Vmkernel Config Option [string] {
   Default value:allflash,stretchedcluster
   valid characters:**
   Current value:
   hidden config option:1
   Description:List of licensed vSAN features for this host
   Host specific config option:0
   Option update requires reboot:0
   Option update requires maintenance mode:0
}
  • Working scenario:
    • vsish -e get /config/VSAN/strOpts/LicensedFeatures
      • Vmkernel Config Option [string] {
   Default value:allflash,stretchedcluster
   valid characters:**
   Current value:vit,allflash,stretchedcluster,erasurecoding,storageefficiency,encryption
   hidden config option:1
   Description:List of licensed vSAN features for this host
   Host specific config option:0
   Option update requires reboot:0
   Option update requires maintenance mode:0
        }

 

Resolution

Follow the below steps to assign a valid license to vSAN cluster. 

1. Log into the vSphere Client.
2. Navigate to Administration > Licensing > Licenses.
3. Ensure a valid vSAN license is available.
4. Navigate to the affected vSAN cluster > Configure > Licensing.
5. Click Assign License, select the valid key, and click OK.
6. Power on the VM to verify resolution.

Note: If the Evaluation license is expired or you don't have the proper license for RAID5/6 which requires a vSAN Advanced license or higher, open a case with our GCA team and acquire the proper licensing.

If purchased licensed features are missing on the host please open an SR with VMware by Broadcom so we can address the issue. 

Additional Information

• Power on or vMotion of any VM in vSAN fails with the error "Module MonitorLoop power on failed"
• How to use the vSAN License on the vSAN cluster