Introducing Elastic Pools

An Azure SQL Database Elastic Pool is a cost-effective solution for managing and scaling a group or pool of multiple Azure SQL Databases, with the utilization pattern characterized by low average utilization and infrequent spikes.

Figure 7.1: Elastic Pools

All databases in an elastic pool:

• Belong to one Azure SQL server

• Share a set number of eDTUs

• Share a set number of elastic pool storage

• Are priced for eDTUs and not individual databases like DTUs

• Can scale up to the given maximum amount of eDTUs

• Have a guaranteed minimum number of eDTUs

When Should You Consider Elastic Pools?

In Chapter 6, Scaling Out Azure SQL Database, we worked on sharding the toystore database into four individual shards. Each shard had 50 pieces of a customer's/tenant's data.

Let's say that each individual database is sized to a Standard S3 service tier, for example, 100 DTUs, and has a DTU utilization as shown in the following graph:

The preceding graph shows the DTU's utilization by time for...