I’ve been working with Symantec’s new VMWare agent for Backup Exec 2010 for the past couple of months. We were excited to have differential backup of VMDK files through vSphere when they announced the new version of the software. In practice however this is a bit more involved than we bargained for.
There are a couple of things that keep us from using this tool to the full extent. First, we have noticed a dramatic decrease in backup speed from the Windows agent to the VMWare agent. The VM agent is about half as fast which impacts our backup windows. Secondly, if you have any VMDK files that are set to ‘independent’ that will cause the VM agent job to fail which hurts your differential backups down the line.
One of the biggest pain points of this agent is that we have regularly been seeing servers fail with the error ‘unable to quiesce’ or some similar variation. Many of the documents out there and support forums have information, but much of it is dated and references VCB which isn’t in use here as Backup Exec 2010 uses the new vSphere API to pull the backups.
I’ve found two quick and dirty ways to try first. First restart the VMTools service on the target Guest to be backed up. Secondly, restart the mgmt-vmware service on the ESX host that the target Guest is living on. More often than not restarting these services fixes the problem, at least temporarily.
I tired setting up a batch file on each of the Guests that would stop and restart the VMTools service. I then put this as a pre-job command in Backup Exec. For the life of me I could not get this to work. I kept getting the error ‘could not find the file’ in the results of the backup job. I believe that the issue is Backup Exec trying to run the command on the ESX server, and not the Windows Guest. Although its not pretty, I’ve scheduled this batch file from within Windows to run every morning. Hopefully this will help keep my backups on track so we can meet our SAS70 objectives.