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DavidC-7877 asked SaurabhSharma-msft answered

DR Plan for AlwaysOn cluster in Azure: Azure Site Recovery vs Asynch AlwaysOn DR node

(Edited 6/17)

We are in early stages of planning SQL Server 2019 AlwaysOn cluster in Azure. The plan for the cluster topology is the conventional 2 x HA nodes in primary region and 1 x DR node in paired region in the same geography. We don't have experience with Azure Site Recovery (ASR) but we know it can be used for region-to-region replication and recovery. We are wondering if we can use ASR to replicate the two HA nodes from the primary region to the paired region instead of using the single AlwaysOn async DR node per conventional cluster topology. The following Microsoft article shows a graphic of replicating the two HA nodes:

https://azure.microsoft.com/en-us/services/site-recovery/

We aren't sure if ASR is feasible to replace AlwaysOn asynch DR node and what is to be gained. Difference in RTO/RPO? Difference in cost? Difference in effort to set up?

azure-sql-database
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Hi @davidc-7877,

Thanks for using Microsoft Q&A !!
I am checking internally on the same. Meanwhile you can check if you are looking for the using disaster recovery as mentioned in the table over here.

Thanks
Saurabh

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Thank you Saurabh. The first row and last row in the table are relevant and indicate that conventional AlwaysOn asynch replica may have lower RPO compared to using ASR to replicate the HA nodes. I look forward to any more feedback that you may have.

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1 Answer

SaurabhSharma-msft avatar image
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SaurabhSharma-msft answered

Hi @davidc-7877,

I have received the confirmation that ASR generate application consistency snapshots between 1hr -12 hours something you can configure. This may add a maximum of 1 hours of data loss in the case of disaster.
Also, the above shared link lists several options to establish DR for SQL Severs or SQL Servers running on Azure VMs and you need to review and choose the right one that fit your needs.

Please let me know if you have any additional questions.

Thanks
Saurabh


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