Two HyperV hosts - Backups work on one host but not the other

[Mike-O]

I've started supporting a customer that has two Windows Server 2008 R2 SP1 machines with the Hyper-V roles installed (Host1 and Host2). They're clustered and hold 6 VMs between them (normally 3 VMs on each host). Backup Exec 2012 SP4 (Hotfix 215906 & 217247) is installed on a separate physical server that runs Server 2008 R2 SP1.

The backups were working smoothly until Host2 was restarted to replace a faulty memory stick. Since then any VMs that are on Host2 fail to backup. The VMs can be migrated from one host to another and the result is exactly the same, so at present the customer is keeping the VMs on Host1 so that they backup each night. This is fine for the short-term but naturally there's no redundancy in the environment and also less resources to run the servers.

The error in Backup Exec is that it simply fails to communicate with the VMs on Host2. I've confirmed this by creating a duplicate backup job, which sees the VMs but fails to view the volumes on Host2 when they're expanded but the ones on Host1 are fine. I've compared the hosts for differences within the operating system and have found the following:

• Host2 has 72 more Windows updates that were applied after the server restart - Host1 has not been updated since August 2014. The correct process would be to update Host1 to be the same, however if this is the issue then I'll have an environment that cannot backup at all so I want to avoid this if possible.
• Host2 has a local GPO that is being applied and Host1 does not. I've looked through the GPO settings but it's hard to see what is applied on local policies. The only differences I've observed are that Host1 has the following settings and Host2 does not:
  • Adjust memory quotas for a process = SQLSERVER2005MSSQLUser$HOST1$MICROSOFT$VMM$
  • Bypass traverse checking = SQLSERVER2005MSSQLUser$HOST1$MICROSOFT$VMM$
  • Logon as a batch job = SQLSERVER2005MSSQLUser$HOST1$MICROSOFT$VMM$
  • Logon as a service = SQLSERVER2005MSSQLBrowserUser$HOST1
  • Replace a process level token = SQLSERVER2005MSSQLUser$HOST1$MICROSOFT$VMM$
  • It's worth noting that these local security groups don't even exist on Host2
• Host2 had the Windows firewall on. I confirmed that the Backup Exec rules were applied and also disabled it.

I'm sure that it's going to be a simple permissions related issue but I'm looking for a little assistance with the diagnostic process as I'm new to supporting Backup Exec.

Thanks in advance.

[maurijo]

What is the error you get in the backup exec job log ?

[Mike-O]

Thanks for the prompt response Maurijo.

Sadly the customer has been running on a single host for some time so the backups have been running smoothly and the logs don't go back far enough to display the error message. The customer is on holiday at the moment and I'll need to get him to move a VM to Host2 and recreate the error early next week.

[maurijo]

No problem, but we will need some kind of error to start troubleshooting :)

Update the thread when you have new info so that we can assist.

[Mike-O]

Hi,

The error is as follows:

Browse Failure

Failure to browse 'VmName (VmName.domain.local)

Backup Exec was unable to open an existing VHD because the VHD may be corrupted or because you may not have logged on as an administrator.

[VJware]

Start off with this KB to ensure the BE account has the appropriate rights on the problematic Hyper-V host - http://www.symantec.com/business/support/index?page=content&id=TECH23689