ESXi configuration backup fails with an error - "A general system error occurred: Internal error"

Products

• VMware vSphere ESXi

Issue/Introduction

When trying to take the ESXi configuration backup on the ESXi via SSH following the KB article - How to back up and restore the ESXi configuration, it fails as below. 

[root@esxi:~] vim-cmd hostsvc/firmware/backup_config
(vmodl.fault.SystemError) {
   faultCause = (vmodl.MethodFault) null,
   faultMessage = <unset>,
   reason = "Internal error"
   msg = "Received SOAP response fault from [<<io_obj p:0x000000ff6b57ca78, h:5, <TCP '127.0.0.1 : 49088'>, <TCP '127.0.0.1 : 8307'>>, /sdk>]: backupConfiguration
A general system error occurred: Internal error"
}

Environment

VMware vSphere ESXi 6.5
VMware vSphere ESXi 6.7
VMware vSphere ESXi 7.0
VMware vSphere ESXi 8.0

Cause

This issue can occur if the downloads folder is missing in the /scratch partition of the ESXi.

Resolution

1. Navigate to the /scratch partition and create a folder called downloads
   
   [root@esxi:~] cd /scratch/
[root@esxi:/vmfs/volumes/<datastore UUID>] mkdir downloads
   
   
2. Take the ESXi configuration backup again 
   
   [root@esxi:~] vim-cmd hostsvc/firmware/backup_config
Bundle can be downloaded at : http://*/downloads/<datastore UUID>/configBundle-esxi.domain.tgz

Additional Information

How to back up ESXi host configuration