Failover of adls Gen2 accounts

Question

I have a two gen2 namespace enabled storage accounts with same location and resource group and I have enabled preview feature for my subscription. Now I could see failover enabled in only one storage account and in other storage account it is disabled. I am not sure why the failover is disabled on storage account.

If anyone has the reason behind this please let me know.

Answer 1

Hello Polamuri Krishna Chandra,

Greetings! Welcome to Microsoft Q&A Platform.

ADLS Gen2 is indeed built on top of Azure Blob Storage, but there are certain limitations. And account failover is one of them and fortunately now this is in Preview with some limitations mentioned over this article.

Customer-managed account failover for accounts that have a hierarchical namespace (Azure Data Lake Storage Gen2) is currently in PREVIEW and only supported in the following regions:

• (Asia Pacific) Central India
• (Asia Pacific) Southeast Asia
• (Europe) North Europe
• (Europe) Switzerland North
• (Europe) Switzerland West
• (Europe) West Europe
• (North America) Canada Central
• (North America) East US 2
• (North America) South Central US

To opt in to the preview, see Set up preview features in Azure subscription and specify AllowHNSAccountFailover as the feature name.

See the Supplemental Terms of Use for Microsoft Azure Previews for legal terms that apply to Azure features that are in beta, preview, or otherwise not yet released into general availability.

if there's a significant disaster that affects the primary region, Microsoft will manage the failover for accounts with a hierarchical namespace. For more information, see Microsoft-managed failover.

Also, for data resiliency with Data Lake Storage Gen2, it is recommended to geo-replicate your data via GRS or RA-GRS that satisfies your HA/DR requirements. Additionally, you should consider ways for the application using Data Lake Storage Gen2 to automatically fail over to the secondary region through monitoring triggers or length of failed attempts, or at least send a notification to admins for manual intervention.

Failover is only supported for storage accounts configured with Geo-redundant storage (GRS) or Read-access geo-redundant storage (RA-GRS). If your storage account is not configured with one of these redundancy options, failover will not be available.

Please note, when in preview the feature is not recommended for production and only Dev/Test environment usage. The below link has the details regarding the availability region details:

https://learn.microsoft.com/en-us/azure/storage/common/storage-disaster-recovery-guidance?toc=%2Fazure%2Fstorage%2Fblobs%2Ftoc.json&bc=%2Fazure%2Fstorage%2Fblobs%2Fbreadcrumb%2Ftoc.json#azure-data-lake-storage-gen2

Hope this answer helps! please let us know if you have any further queries. I’m happy to assist you further.

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Answer 2

@Polamuri Krishna Chandra, Adding more information to the above response!

Can you please share the screenshot of disabled Storage account?

It sounds like you're experiencing an issue with the failover feature on your storage accounts. There could be several reasons why failover is disabled on one of your storage accounts, even though both are in the same location and resource group.

One possibility is that there might be a temporary service issue or bug affecting the failover feature. For instance, there have been instances where the customer-controlled failover feature was disabled due to severe service issues. It's also possible that the failover feature is temporarily disabled for maintenance or other operational reasons.

Another reason could be related to specific configurations or limitations of the storage accounts. For example, certain features or settings might need to be enabled or configured correctly for failover to work as expected

To resolve this issue, I recommend checking the following:

1. Ensure that both storage accounts have the same configurations and settings.
2. Verify if there are any ongoing service issues or maintenance activities that might be affecting the failover feature.
3. Check if there are any specific requirements or limitations for enabling failover on your storage accounts.

If the issue still persists, I would like to work closer on this issue. Please share Storage account details in Private message.

References

Failover considerations for storage accounts with private endpoints - Azure Storage | Microsoft Learn
Initiate a storage account failover

Please let us know if you have any further queries. I’m happy to assist you further.   

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