Azure VM Backup failing: It’s time to switch to private preview of disks greater than 1023 GB

Recently we have faced issues related to the backup of the Azure VM, the VM is a newly build Azure IaaS server. While taking the snapshot backup of the Azure VM we have found that that we are unable to take the backup and this VM and this is the error message that is generated in the screen.

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UserErrorUnsupportedDiskSize – Azure Backup does not support disk sizes greater than 1023GB.


In this case you can join the private preview for large disks (>1TB). The same preview can be used to support faster recovery point creation, using those recovery points during restore to improve on rest.


How can you enable this feature?

You need to execute following cmdlets from an elevated PowerShell:

1) Login to Azure Account: Login-AzureRmAccount

2) Select the subscription which you want to register for preview: Get-AzureRmSubscription –SubscriptionName “Subscription Name” | Select-AzureRmSubscription

3) Register this subscription for private preview: Register-AzureRmProviderFeature -FeatureName “InstantBackupandRecovery” –ProviderNamespace Microsoft.RecoveryServices

It will take around two hours to complete the registration process. You can use the following cmdlet to check registration status. You need not change anything in your schedule or policy for this to take effect.


Get-AzureRmProviderFeature -FeatureName “InstantBackupandRecovery” –ProviderNamespace Microsoft.RecoveryServices

This will not impact you infrastructure. You just cannot perform any change on the backup policy or schedule as mention above.

The cost will be the same for the ones you already have in place.


What are the additional costs incurred when signed up for the private preview for support of azure backup with large disk (Greater than 1 TB)?

Since MS store snapshots to boost recovery point creation and also to speed up restore, you will see storage costs corresponding to snapshots for the period 7 days(currently snapshots will be kept for 7 days – this is fixed and we have plans to make this a choice in coming releases).

Please refer the below doc shared by azure backup product team:

Is there any impact on the production server upon signing up to private preview for larger disk backup on azure VM?

There is no impact on production server.

Any ETA on GA?

It isn’t announced publicly yet, but as per the PG it is GA at the end of March 2018 tentatively.


In case you have larger disks it’s good idea to switch in to private preview. It’s a seamless movement and doesn’t affect your production environment.

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