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What I'd like to achive is to be able to scale out Azure SQL Database.

Business Critical tier has this feature to enable several read-only replicas. This is a great feature that would let me offload some traffic over to those replicas

The problem for me is that I don't understand how to manage those replicas and I don't understand how load balancing works there. Basically, I should be able to manage how many replicas there are, I probably need to have around 10 of replicas and have traffic equality balanced across them

Is this something that I could do?

Stanislav
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  • Have you seen this document https://learn.microsoft.com/en-us/azure/azure-sql/database/read-scale-out ? – Leon Yue Aug 18 '20 at 01:35
  • @LeonYue , yes, thank you. It doesn't really answer those questions. It only says that for Business Critical tier it creates several replicas. It doesn't really say how I could add more replicas there or how I could load balance traffic across those replicas – Stanislav Aug 18 '20 at 02:45
  • yeah, it seams that there are no enough documents talked about this. I searched on Portal and googled, but find nothing. – Leon Yue Aug 18 '20 at 02:52

1 Answers1

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If you look at the note here, it says

In Premium and Business Critical service tiers, only one of the read-only replicas is accessible at any given time. Hyperscale supports multiple read-only replicas.

This means Premium and Business critical service tiers may have multiple replicas (3-4) but only 1 of them is accessible as read only. There is no control as to which one and there is no load balancing capabilities. It is only good for use if there is a separate application which require read access only (example analytical workloads).

For Hyperscale you can refer to this. Hyperscale allows for 1-4 secondaries(1 by default). The link states

If more than one secondary replica is present, the workload is distributed across all available secondaries.

There is no additional information and it seems the the control to load balance is abstracted away from us. You can definitely not achieve your requirement of 10 read replicas from any of these configurations.

General Grievance
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Anupam Chand
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