Azure DB Pricing with Elastic Pools

Question

I'm trying to get an idea of how much databases will cost in Azure.

I've created an Elastic database pool and it says the monthly cost would be R2580 (South African Rands) for up to 200 databases & 100 eDTUs.

If I go to any of the databases I've created in the pool, and click on the Pricing Tier, it says it's a Basic database with 5 DTUs and estimated cost of R85 per month.

So what am I going to pay? R2580 per month, or (R85 x n databases) per month, or both?

Presumably, it's R2580 per month. If that's right, then you have to have at about 30 databases before the prices even out, and even then you're probably better off with the stand-alone databases as you'd have 150 DTUs vs 100 eDTUs.

Is my logic correct?

Answer 1

So what am I going to pay? R2580 per month, or (R85 x n databases) per month, or both?

You're going to pay R2580 / month as all the databases are part of an elastic database pool.

Presumably, it's R2580 per month. If that's right, then you have to have at about 30 databases before the prices even out, and even then you're probably better off with the stand-alone databases as you'd have 150 DTUs vs 100 eDTUs.

You're right again. Elastic Database Pools serve a different use cases and may not be a right solution in every scenario. Typically Elastic Database Pools become useful if you have a multi-tenant SaaS application where each tenant gets a different database and there's a varied consumption pattern for each tenant. With individual databases, you would be capped at the DTU limit of that database. With Elastic Database Pools, your tenants can share the eDTU of that pool and can occasionally go beyond the DTU for that of an individual database.

You may find this link helpful in understanding when it makes sense to use Elastic Database Pool: https://azure.microsoft.com/en-in/documentation/articles/sql-database-elastic-pool-guidance/.