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Commvault 11.30.25

HyperV 2016 & 2019

 

Until recent, we received the windows system event 153 when Commvault backed up our virtual domain controllers.

153 = The IO operation at logical block address 0x95e8e70 for Disk 5 (PDO name: \Device\0000054c) was retried.

The device id would change per event. The disk counter would always be one or two higher than the actual disk count on the machine.

The Commvault log confirms that disk 5 (in this case) is being used for mounting a VM snapshot.

 

It seems that when Commvault dismounts the VSS snapshot, Windows isn’t quite up to date yet when monitoring some IO. I never understood exactly what the problem was or why it only showed up for those machines.

 

However, from the beginning of this week, we’re seeing a lot more of these events, i haven’t counted them out yet, but there are enough that it might be one or more for every VM.

 

So this needs to be solved, because clearly something is going on and it becomes increasingly difficult to maintain an environment with that many alerts.

 

Anyone already had an issue like this?

 

 

 

Hi @Ben Van Doorsselaere ,

We had a few customers with that issue.

Can you check you have any Hardware issues?

Can you check the MS Article if not done already: https://support.microsoft.com/en-us/topic/useless-characters-are-logged-in-event-id-153-in-windows-cf9e9a0a-8936-fbb0-0074-36b7e69bb5ff

As we are just taking virtual machine checkpoints so we don’t have any control on how the request might come down to volsnap.

Can you check with the Microsoft Team and log a case with Microsoft to provide a bit more on what they are observing there please?

You can also log a case with Support and we will check.

Best Regards,

Sebastien

 


No hardware issues

I don’t have the issue described in the article 

MS already contacted when the alert was only showing up for our domain controllers. they didn’t find anything, the would only confirm that it doesn’t pose a problem.

 

Hyper-V nodes rebooting during backups | Community (commvault.com)
This article pointed out to me that I have automount enabled.
I’ll be changing that to see if it helps mitigate the alerts.


Setting the automount to disable didn’t help.

However, I do notice that the servers with the alert, keep certain snapshot files mounted to the OS (visible in disk manager)

These images come from C:\Program Files\Commvault\ContentStore\iDataAgent\JobResults\PseudoMount\Transient

these mount points disappear as soon as I stop the commvault services.
Where would I be able to find the cause of this failure to dismount?


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