Question

Azure Replication / Sync failed

  • 16 May 2023
  • 5 replies
  • 129 views

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Hi! We are trying to replicate an Azure VM to a storage account located in a different region. Backup of the virtual machine worked, but when trying to use the “Replicate now" prompt, replication fails due to a sync error. Further investigation into the replication group/VM showed the error “One of the disks exceeds the maximum allowed size for an Azure VHD page blob". Is there a way to work around this? Specially that we are planning to replicate even larger capacity VMs. Any help is greatly appreciated 


5 replies

Userlevel 2
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Hi Paul,

 

It should say which disk is throwing that error but if you check the source VM, does it have any disk that’s larger than 8TiB (8191GiB)? 

 

The limitation seems to be from this: 

 

What is the largest supported page blob size?

The largest page blob size that Azure supports is 8 TiB (8,191 GiB).

https://learn.microsoft.com/en-us/azure/virtual-machines/faq-for-disks

 

Let’s confirm the size of the disks and go from there.

 

Thank you for your time.

Kind regards,

Jiye Lee

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Hi Jiye, 

Currently, the largest disk in the source VM is 4.7TB but only 2.1 TB is consumed which is why I am not sure why that error comes up. 

Thank you for your response

Userlevel 2
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Hi Paul,

 

It’s good that you don’t have any 8TiB disk.

 

If it’s 4.7TB disk, it shouldn’t throw that error. At this point, I would need to check the vsrst log. 

 

Do you have access to our ma.commvault.com website?

Could you raise a case either on the ma website or by contacting our hotline? https://ma.commvault.com/Support/TelephoneSupport

Then if you can send us the logs, I’ll take the case and check the vsrst.log. 

 

Thank you for your time. 

 

Kind regards,

Jiye Lee

Userlevel 7
Badge +23

Hi Paul,

 

It’s good that you don’t have any 8TiB disk.

 

 

 

Kind regards,

Jiye Lee

In the same link I am seeing a caveat that only 4 TB is supported when attached to a VM?

What is the largest supported page blob size?

The largest page blob size that Azure supports is 8 TiB (8,191 GiB). The maximum page blob size when attached to a VM as data or operating system disks is 4 TiB (4,095 GiB).

 

This reads to me that you could provision a large 8TB disk but would not be able to attach it?

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Hi Damian, 

Is this due to my data disk being more than 4TB? I have a separate OS disk of 126GB and a data disk of 4.7TB. 

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