Host-based backup of Microsoft Hyper-V VMs.
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IDEIT
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VSS wait timeout

Post by IDEIT »

Does this apply to Hyper-V or does it only apply to vmware?

https://www.veeam.com/kb1377
Gostev
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Re: VSS wait timeout

Post by Gostev »

Should be both, as the guest processing logic is shared.
IDEIT
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Re: VSS wait timeout

Post by IDEIT »

I have one Hyper-V host where every single guest OS backup started failing at the exact same time with the following errors.

[22.12.2020 00:25:05] SnapCreator| ERR |Unknown status of async operation
[22.12.2020 00:25:05] SnapCreator| >> |The specified object was not found.
[22.12.2020 00:25:05] SnapCreator| >> |--tr:Failed to create VSS snapshot.
[22.12.2020 00:25:05] SnapCreator| >> |--tr:Failed to perform pre-backup tasks.
[22.12.2020 00:25:05] SnapCreator| >> |An exception was thrown from thread [6888].

I was told the above errors are pointing to a freeze issue and the KB could possibly fix my issue. Does that seem right?
Mildur
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Re: VSS wait timeout

Post by Mildur »

What is the state of your VSS Writers?
Are they failed? If yes, you have to restart specific services or reboot the vm.
A failed VSS Writer cannot do a VSS Snapshot.

You can check your vss writer state with the following command:

Code: Select all

1. Open CMD or Powershell
2. Write: vssadmin list writers
VSS Writers:
https://www.veeam.com/kb2041
Product Management Analyst @ Veeam Software
PetrM
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Re: VSS wait timeout

Post by PetrM »

@IDEIT Could you please share a support case ID for the issue? Looks like debug logs analysis is required but we cannot provide it over the forum posts.

Thanks!
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Re: VSS wait timeout

Post by IDEIT »

PetrM ...

I am trying to get an independent opinion on this from a second Veeam professional first. Do those specific log entries somehow point to a freeze issue?

That KB indicates it applies specifically to AAIP but what if we are not using AAIP?
PetrM
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Re: VSS wait timeout

Post by PetrM »

I understand but it's anyway better to leave logs analysis to our support engineers because our possibility to troubleshoot technical issues via forum is quite limited. Also, I'd recommend to avoid posting debug logs snippets and provide a support case ID instead, as requested when you click New Topic.

The main goal of AAIP is to create transactionally consistent VM backup or replica. Moreover, AAIP allows us to collect an auxiliary information about guest OS and applications so that we're able to perform application items restore. Therefore, disabling of AAIP cannot be considered as a permanent solution.

Thanks!
IDEIT
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Re: VSS wait timeout

Post by IDEIT »

Can I please just get an independent straight answer to my very direct and simple question first?

From there we can move forward with a support ID.
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Re: VSS wait timeout

Post by Gostev »

It's not really a simple question in case of Hyper-V though, because it also uses VSS for the actual image-level backup. So whether or not you use AAIP, VSS will still be in play - and it's hard for us to say from those log snippets you provided what do they relate to.
IDEIT
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Re: VSS wait timeout

Post by IDEIT »

I 100% agree and your response (Gostev) is exactly what I was going for. It is not what I would consider a simple question however it was presented to me as a answer in my case. It just did not seem there was evidence to directly point to this so I was confuised.

Just an FYI, it did not provide any fix to those errors.

Here is a new question... are there any log entries that show that the freeze process did actually succeed? I looked and only found the following:

Operation 'PrepGuest4Freeze' succeeded.

This seems to point to the prep but not the actual freeze process.
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Re: VSS wait timeout

Post by IDEIT »

By the way PetraM, I was not trying to get technical support here. I submitted a case for that and why I did not feel the need to post a support case ID.

I was asking a question to get some specific clarity to what seemed to be a random suggestion.

It was nothing more than simply trying to understand some log entries and how or what they would point to.

Is one not allowed to ask questions to get some better understanding?
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Re: VSS wait timeout

Post by Gostev » 1 person likes this post

You certainly can ask questions, as long as you reference the support case ID for the issue or error you're inquiring about. This is explained in great details when you click New Topic, so please be sure to review it.

Also, please note that it's not about whether you "feel" or not the need to post the support case ID. The forum rules require referencing the support case ID when posting questions about any technical technical issue on these forums. So, if you choose to participate in this community, you must follow these rules - simple as that! Otherwise, please know that there are at least three other Veeam Communities on the Internet that don't have such a requirement :D
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Re: VSS wait timeout

Post by PetrM »

Hello,

@IDEIT You are very welcome to ask any kind of questions related to our product! We need to have a support case ID as a reference because it will help us to be aware of the root cause of the issue once it's resolved and probably share this information with the whole community when the same question pops-up for the next time.

All attempts to interpret log entries via forum are just the attempts to "guess" their real meaning. In most cases these hypothesis are wrong and waste of each other's time on trying irrelevant tests or workarounds, but sometimes can provoke even more serious problems. Also, I would definitely give a suggestion for research if I had it but the best action plan now is to continue working with our support team.

Thanks!
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