Multiple VSS Snapshots in parallel not allowed

Question

Hello,

When i tried to take shadow copies for multiple drives at the same time in a script, it fails with an error "already snap creation is in progress".
May i know the reason why across different drives also i was not able to take the snapshot simultaneously, Is there any specific reason.
Any information on this would be of great help.

Thanks in advance for your time.

Answer 1

Hi,

Thanks for posting on our forum!

Basically, as you assumed, VSS snapshots are created one by one. In other words, if previous VSS snapshot has not completed properly and is still running, you can run into this error message. Here are certain reasons ans corresponding solutions to your issue:

1. More than one backup program installed (reason).

If you have more than one backup program installed on your machine, disable all of the programs except for one and try running the backup job again.
2. Previous VSS snapshot has not completed properly and is still running (reason).

Stop and Re-start the Volume Shadow Copy service. You can do this by going to Control Panel > Administrative Tools > Services.
Once in Services, find Volume Shadow Copy and right click and select Restart.
Also a reboot of the machine is been known to clear this issue.

Thanks for your support and understanding! Besides, if you think my answer is helpful, would you please help me Accept Answer. An accepted blog can be put on top of our forum, so that people who have a similar issue can get access to their solution more quickly.

BR,
Joan

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Answer 2

Thank you Joan.

Sorry for not been so clear on my request.

I don't see any issues with snap creation, it did not hang or in progress for long time.
My query is why can't we take snapshots in parallel rather simultaneously on two different drives ( for ex E and F).
Is there any reason why vss snapshots are serial.

Thanks!

Answer 3

Hi,

Thanks for your quick reply!

You can operate parallel VSS backups, but you need to stagger the start time of the backups by at least 10 minutes. This interval ensures that the snapshot operations do not overlap. If backup operations overlap, a VSS timeout error may occur, and the second backup request may fail. This may be the reason for your error message. In addition, you should configure the parallel instance backups so that snapshots of the same volumes are not created and should ensure that parallel backups do not create a snapshot of the same LUN.

Thanks for your support!

BR,
Joan

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Answer 4

OK. Thanks.

What enforces VSS to limit this parallel snap creation is the information i am missing to get it.