Issue:
You receive one or more of the following error messages when running a vcbMounter backup.
In VirtualCenter you receive on of the following messages
Create Virtual Machine Snapshot: A general system error occurred: protocol error from VMX
Create Virtual Machine Snapshot: Operation timed out
In the vcbMounter Log
Error: Other error encountered: Snapshot creation failed: Operation failed since another task is in progress.
Error: Other error encountered: Snapshot creation failed: Operation timed out.
Error: Other error encountered: Snapshot creation failed: System error
Error: Other error encountered: Snapshot creation failed: Custom pre-freeze script failed.
Cause:
One of several services may have stopped responding or may have other issues. This is very noticeable by the fact that the error messages returned may change as you try the various solutions given below.
Solutions:
All these issues are pretty common and have one of several simple solutions. The one that will work for you will be found by trail and error or may differ each time you encounter the error. Sometimes, you may need to do more that one thing to get the vcbMounter backup to work.
Method 1
Restart the Host Agent (mgmt-vmware) service on the ESX host where the VM is located.
service mgmt-vmware restart
Suggested method for resolving this error, but does not always work by itself.
Error: Other error encountered: Snapshot creation failed: Operation failed since another task is in progress.
Method 2
On the Guest OS restart the VMware Tools service.
Suggested method for resolving the following errors, but not always, may require Method 4 and 5 as well.
Error: Other error encountered: Snapshot creation failed: Operation timed out.
Create Virtual Machine Snapshot: A general system error occurred: protocol error from VMX
Method 3
On the Guest OS un-install and re-install VMware Tools. This will require the OS to be restarted after the un-install then again after the re-install. Make sure to do a complete install of VMware Tools. Try this only after Methods 2, 4 and 5 have been attempted.
Suggested method for resolving the following errors, but not always, may require Method 4 and 5 as well.
Error: Other error encountered: Snapshot creation failed: Operation timed out.
Create Virtual Machine Snapshot: A general system error occurred: protocol error from VMX
Method 4
Restart all the following services on the ESX host where the VM is located.
- Host Agent
- service mgmt-vmware restart
- Authorization Daemon
- service vmware-vmkauthd restart
- VirtualCenter ESX Agent
- service vmware-vpxa restart
Suggest method of for resolving any error listed above.
Method 5
Append to the end of the vcbMounter command the –Q 0 switch. This allows the backup to proceed without forcing the OS to quiesce the disk I/O.
This method is the suggested solution for the following error, but also works in combination with Method 4 to address any of the other errors as well.
Error: Other error encountered: Snapshot creation failed: Custom pre-freeze script failed.