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How does disabling Volume Shadow Copy affect a backup/image?

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Beginner
Posts: 1
Comments: 1

Hello.

I hope someone can help me with this query please?

I'm having problems taking images on a couple of PCs - it says the image completed but with warnings. The warnings are all to do with VSS. If I edit the settings when taking an image and do not use volume shadow copy, this seems to allow the image to be created without warnings.

What does this do to the image? What could go wrong? Isn't VSS needed to create images on "on-the-fly"?

Many Thanks,

EddieC.

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Frequent Poster
Posts: 2
Comments: 549

Hello EddieC,

If you disable VSS, our own SnapAPI snapshot technology is used instead. This gives you a consistent image "on-the-fly" even if VSS is not available.

However, unlike VSS, our own snapshot does not send pause requests to databases. If you are running a database with VSS support (Active Directory services, MSSQL, Exchange, etc.), using it is required if you want a guarantee of a consistent database in the image. It is absolutely required for Domain Controllers. 

If you are not running VSS-aware applications on these PCs, then it doesn't really matter.

Beginner
Posts: 1
Comments: 1

Thanks Igor.

Forum Hero
Posts: 62
Comments: 7495

Hi Igor,

01) Does this apply to all Acronis products? If so, that is good to know.  I have had a long standing support case open with ATIH regarding the failure of one of my systems to successfully backup to the Acronis Cloud that has not been resolved.  I could always start the backup and it would get to 1GB and then stop and never progress.  If I delete the job locally or in Acronis cloud and create a new one, it would start from scratch and fail at around 1GB again and then continue to keep failing, as well.  Unfortunately, nothing in the logs or any of our troublehshooting has pinpointed the cause and I had just about given up.

On a hunch from this forum and another one I saw from MVP Enchantech in another ATIH post recommending to disable VSS, I went ahead and did this and low and behold, the Cloud backup for this trouble system is now running fine.  I'm a little concerned that VSS and Acronis are competing when VSS is enabled, but am glad for the work-a-round as it seems to be system specific in this case and I don't have any databases running on this system..  

02) Will disabling VSS have any adverse impact on Windows ability to maintain, backup and/or restore files or folders under Windows Protection / Previous Versions?

Frequent Poster
Posts: 2
Comments: 549

Hello,

It should apply to True Image as well.

Disabling VSS in favor of our own snapshot shouldn't cause any problems for regular systems.

However, it is definitenly not recommended if you are running VSS-aware databases (like MS SQL).

And it should never be done if you have a domain controller. A DC backup without VSS will most likely cause a BSOD after restoration, so the backup will pretty much be useless.

JJR
Beginner
Posts: 0
Comments: 1

Hello, 

Forgive me for resurrecting an old thread. I am contemplating a similar question. I am having endless issues with VSS on my Windows Server Essentials 2016. The server is a DC. Backups keep failing with the error: 

Windows error: (0x800423F2) VSS writer 'System Writer' with class ID 'E8132975-6F93-4464-A53E-1050253AE220' has timed out. This may be caused by too intensive I/O on the machine at the backup start time. Try to re-schedule the backup to some different time. To troubleshoot VSS issues, download and run Acronis VSS Doctor available at https://www.acronis.com/en-us/personal/vss-diagnostic-free-tool/

I have an open case with Acronis support as we speak and will report back for the benefit of others if (hopefully) we have a resolution to this. 

In the interim, I have to reason that a successful backup with VSS disabled and without "Application Backup: Microsoft Active Directory" selected in the backup plan, is better than having no backups at all. The domain only has less than 10 users with seldom changes to AD. 

Will any potential full server restorations in the future really be unusable / corrupt?

One additional change I made was disabling and deleting shadow copies on the drives, in an attempt to reduce I/O load - Link here. Is this a dangerous idea? 

Forum Moderator
Posts: 113
Comments: 4340

Hello JJR,

Basically, you can recover a backup of a domain controller made without VSS, but in this case you'll need to take measures to avoid a USN rollback, please refer to Avoiding a USN rollback