Hyper-V VSS Writer VSS_WS_FAILED_AT_PREPARE_SNAPSHOT

[AlexLeadingEdge]

Hi guys! I'm seeing this error, any help would be appreciated. I'll open a support case for it now and will reply with the Case ID #. I have rebooted the machine but no change.

Failed to create snapshot (Microsoft Software Shadow Copy provider 1.0) (mode: Veeam application-aware processing) Details: Writer 'Microsoft Hyper-V VSS Writer' is failed at 'VSS_WS_FAILED_AT_PREPARE_SNAPSHOT'. The writer experienced a non-transient error. If the backup process is retried, the error is likely to reoccur. --tr:Failed to verify writers state. --tr:Failed to perform pre-backup tasks.
Make sure VM does not have 'iSCSI Software Target Storage Provider' feature installed.
Retrying snapshot creation attempt (Writer 'Microsoft Hyper-V VSS Writer' is failed at 'VSS_WS_FAILED_AT_PREPARE_SNAPSHOT'. The writer experienced a non-transient error. If the backup process is retried, the error is likely to reoccur. --tr:Failed to verify writers state. --tr:Failed to perform pre-backup tasks.)
Task has been rescheduled
Queued for processing at 7/06/2016 7:57:24 a.m.
Unable to allocate processing resources. Error: Writer 'Microsoft Hyper-V VSS Writer' is failed at 'VSS_WS_FAILED_AT_PREPARE_SNAPSHOT'. The writer experienced a non-transient error. If the backup process is retried, the error is likely to reoccur. --tr:Failed to verify writers state. --tr:Failed to perform pre-backup tasks.

[AlexLeadingEdge]

It only started doing this yesterday morning. As far as I know no changes have been made to the system.

[AlexLeadingEdge]

Ticket #1819629

Problem solved!

Mike (VEEAM)

Select the backup job, right click Edit... > Guest Processing > untick Enable Application-Aware Processing. This is only needed for Domain Servers, Exchange Servers, SQL Servers and Sharepoint Servers.

[Moccamaster]

I have been hit with the VSS_WS_FAILED_AT_PREPARE_SNAPSHOT and non-transient error, and wondered what others have done to fix it.

22-06-2016 03:22:41 :: Retrying snapshot creation attempt (Writer 'Microsoft Hyper-V VSS Writer' is failed at 'VSS_WS_FAILED_AT_PREPARE_SNAPSHOT'.
The writer experienced a non-transient error. If the backup process is retried,
the error is likely to reoccur.
--tr:Failed to verify writers state.
--tr:Failed to perform pre-backup tasks.)

According to other posts like microsoft-hyper-v-f25/hyper-v-vss-write ... 35736.html, disabling application-aware backups will fix it, as its only needed for SQL, Exchange, Active Directory etc.

My guest VM is running MS Exchange 2013 fully updated, and thus I need the application-aware setting.

I checked avail disk space for all VHDs and there should be enough. I have not logged at case yet, as I would first check forums out and see if others have similiar issues and possible solutions.

Setup is:
HOST, Windows 2012 R2 fully updated running HYPER-V
GUEST, Windows 2012 R2 fully updated running Exchange 2013 and Active Directory.

All VSS services are running as expected, and other VM on the host seems to backup as expected (no errors in the history log).

[PTide]

Hi,

Have you checked the writer's state using the 'vssadmin list writers' command?

Thanks

[Moccamaster]

Yes, all writers are running with "Stable" and "No error", like this:

Writer name: 'Microsoft Hyper-V VSS Writer'
Writer Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}
Writer Instance Id: {8d5a93da-e3bb-4a18-8f2c-ce801492d83a}
State: [1] Stable
Last error: No error

Eventviewer:

A VSS writer has rejected an event with error 0x800423f4, The writer experienced a non-transient error. If the backup process is retried,
the error is likely to reoccur.
. Changes that the writer made to the writer components while handling the event will not be available to the requester. Check the event log for related events from the application hosting the VSS writer.

Operation:
PrepareForSnapshot Event

Context:
Execution Context: Writer
Writer Class Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}
Writer Name: Microsoft Hyper-V VSS Writer
Writer Instance ID: {8d5a93da-e3bb-4a18-8f2c-ce801492d83a}
Command Line: C:\Windows\system32\vmms.exe
Process ID: 2872

[PTide]

Hi,

It seems that something is wrong with the VSS writer. The best you can do is to contact Veeam technical support so they can confirm the issue. Please provide your support case number once you get it.

Thanks

[Moccamaster]

Support case created ID #01834628

[-=MACROS=-]

Hi guys,

Be sure you've enought free space on child partition on vServer firstly (it's include all disks on vServer you want to back up).

The second one, under advanced file option on each partition (that should be back up) set Volume Shadow Area to unlimited and than proceed backup.

Hoply these stepps can help you.

Let us know if it helps.

Good luck

[Moccamaster]

After opening an incident with Microsoft, the issue have been solved.

Note! This issue was purely related to the VSS backup process, other backup software that uses VSS also failed (tested with MS windows server backup).

The culprit was a snapshot that should have been merged but wasnt. A reboot of the VM host server solved the issue in my case.
After reboot the Snapshot waas automerged and all worked just fine.

[Andy_Morgan]

I'm trying to backup our File Server, the server runs Microsoft shadow copies twice a day, but i'm also now trying to backup the VM which is around 5TB of Data

I have backed up all my other servers with no issues at all, the error i get is a follows

28/10/2016 08:45:48 :: Unable to allocate processing resources. Error: Writer 'Microsoft Hyper-V VSS Writer' is failed at 'VSS_WS_FAILED_AT_PREPARE_SNAPSHOT'.
The writer experienced a non-transient error. If the backup process is retried,
the error is likely to reoccur.
--tr:Failed to verify writers state.
--tr:Failed to perform pre-backup tasks.

[foggy]

Andrew, please review this thread for the hints and contact support in case nothing helps.

[Shestakov]

By the way, there is a Veeam ONE report called Configuration Assessment which you can use to analyze configuration of the Hyper-V infrastructure against a set of recommended settings and best practices. Report is available in free version of the product.