Tag Archives: avamar

Adding vCenter to Avamar – Failed to communicate to vCenter

Actually I’m working more and more with some of EMC’s (new Dell šŸ˜‰ ) products for a customer.

On the actual situation we had to add the vCenter Server to theĀ new Avamar Server. While I was adding the server, I received the following message:

Failed to communicate to vCenter. Unable to find valid certification path to the vCenter



After searching a while in the Avamar for VMWare Admin guide I’ve found the solution. You either can add the certificate to the Avamar cert store (this would be the secure way) or you just can disable this check.

As our customers environment is not a high secure domain, we have choose the second way. For this we connected to the Avamar server by ssh. Please useĀ the admin user for this.

Then go to the following directory and edit the mcserver.xml:


In the xml search for the following string:

Then change the value from false to true:



Now we can restart the MCS server and the vCenter will be added successfully:


Now the vCenter was added successfully:


Snapshots with quiescing fails directly after starting the snapshot

A new customer who I’m working for, has Avamar from EMC as their backup solution for VMware and all other products.

By chechking the activities of the backups, I’ve seen that both Exchange Server VM backupsĀ fails every night.

After having a look at the Avamar logs, i found an error indicating some problems with quiescing:


avvcbimage Error <17775>: Snapshot ‘Avamar-1430951406e32d32fac65d442458b882c72e09fdd7bd3b0a79’ creation for VMĀ <PATH_TO_VM> task creation encountered a quiesce problem (Log #2

So first of all I tried to make a manual snapshot with the quiesce flag from the vCenter:


Directly after the snapshot started, it failed again with the following message:


An error occurred while quiescing the virtual machine. See the virtual machine’s event log for Details.

For me this was now clear that this had to be a vmware related problem. As the error message recommended, I checked the event log of the virtual machine witch is normally located in the VM Folder on the datastore. Scrolling around on the log, I’ve found e interesting error message:


ToolsBackup: not enough empty nodes (needed 8, found 7)

For some reason the VM is saying that the SCSI Controller has no more empty nodes. By searching in the vmware knowledge base, I have found a KB article where this Problem was explained: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1037071

When you use quiescing for snapshooting a VM, you can’t add more than 8 disks to a SCSI controller. Normally you can add up to 16 disk to one controller.

It seems like when you snapshot the disks with quiesce option, vSphere adds an additional disk for each disk that is attached. This must be the reason.

So the only way to resolve this problem, was to add an additional SCSI Controller and attached 4 of the disks to the second controller. After this, the VM was snapshoted without any issues: