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Failed to mount one or more virtual disk images:

Created: 28 Nov 2012 | 14 comments

A number of our esxi 5.0 virtual machines have started checking up the error message:

V-79-57344-38721 - Failed to mount one or more virtual disk images:

When performing incremental backups, full backups have been fine. I've run backups without Advanced File Open run jobs to backup just the affected virtual machines, rebooted everything from VMs to hosts to the backup exec server. Agent based backups of the servers in question are fine and the backups where working fine a couple of weeks ago any suggestions anyone?

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ZeRoC00L's picture

Do you have this hotfix installed:

It fixes this issue:

- Backup of a virtual machine using the Agent for VMware Virtual Infrastructure (AVVI) completes with the following exception when GRT is enabled: "V-79-57344-38721- Failed to mount one or more virtual disk images" (TECH179734)

If this response answers your concern, please mark it as a "solution"

ZeRoC00L's picture

Does the VM in question has independent disks ?

If this response answers your concern, please mark it as a "solution"

Tallwood6's picture

Nope no independent disks and there are no outstanding snapshots on any of the VM's either.

ZeRoC00L's picture

Are you creating a backup through vCenter ?
If so, can you please try to create a backup directly through the ESX host, to see if that works.

If this response answers your concern, please mark it as a "solution"

Tallwood6's picture

I can give it a try but its backing up other servers on the same host fine through vCenter.

Jirka's picture

I have a same problem. Hotfix 180964 is installed. I backing up about 130 VMs. One of this is ending with this exception every time of Full or incremental backup. Many other VMs caused this exceptions randomly. Backup is over SAN. I exclude one problematic VM to separate job and try to setting it to use NBD. Backup jobs ending with same exception again.

Does it make sense to send issue to support?

Tallwood6's picture

I've been working with support on this and i have it working but as long as I dont use SQL GRT. I'm using the SAN & NBD transport modes. Support have been next to useless in actually calling me or updating the call so i've not progressed much further.

Also having occasional issues with the snapshots just freezing and i have to manaully cancel them and consolidate the vms.

lmosla's picture

On the backup jobs for virtual machines with GRT enabled the Backu Exec Agent needs to be installed.  Please see this

Tallwood6's picture

Agent is installed it will do GRT backups of AD, SQL seems to cause issues.

Tallwood6's picture

Trying to replicate the issue in a sperate job at the moment but replicate the issue with SQL GRT. Getting a little bit tired of both the product and support, i dont have much faith in the virtual backups and am wondering if i should just switch to agent based backups for each VM.

lmosla's picture

There is a hotfix that you need to istall.  It has just been released this morning

Keep me updated.

psj_symhelp's picture

run the live update on media server to apply all hotfix. update remote agent on remote server.

try to run backup and check.

if problem not solve share job log for troubleshutting.

King_Julien's picture

Got the same problem here, the backups were working fine and then suddenly this last monday started to fail, I changed from hot add to ndb and nothing change, I just launched the backup without GRT for Exchange, let's see what happens.

There were no changes in the enviroment, in fact we were happy because the backups were working fine, "if it's working, don't touch it". 

A second of your life, ruined for life.