If you have multiple SQL databases in Azure and looking for a centralized management solution, then Elastic Database Pool is the one you’ve been looking for.
Elastic Database Pool is a feature that you can enable in SQL Database Servers which has V12 update. Elastic Database Pool is still in preview as of this writing, so you should agree the preview terms in order to use this.
Azure Elastic SQL Database Pool allows you to manage different databases at a centralized single user interface. This is a breeze feature especially if you have a SaaS application running on Azure with the single tenant strategy for your database layer. You will have different databases for each customer and rolling out updates on each database is not only a time consuming task, but also very annoying and error prone task too. Most of the developers use scripted tools either purchased from some third parties or build their own custom tools to manage collection of SQL databases. But with the introduction of Azure Elastic Database Pool, you can centrally manage your SQL databases as group.
You can add / remove any database to and from the pool when desired, apart from the centralized management – which is a very important feature for devs, cost wise benefits also possible in Elastic SQL Database Pool. Because the pool has a DTU count which is known as eDTU (elastic data through put units) shared across the databases in the pool. So there’s no fixed DTU allocation for the databases.
For example, consider that your application has customers across the globe and the database usage varies based on the time zone. If you’re using SQL Databases without adding them to the pool, you have to allocate a fixed DTU (let’s say 50) for each customer database. Assuming you have 2 databases, each has 50 DTUs allocated and are in different time zones. Your application has traffic only in the day time, during the night the DTUs are unused but you’re still paying for that tier.
But if you can put those databases in an Elastic Database Pool with an eDTU of 50 or little bit more than 50, both databases will run smoothly at a reduced cost. Because when one database is not in use the Elastic Database Pool will allocate the eDTUs to the other database. And also Elastic Database Pool has the flexibility to set the minimum and maximum number of eDTUs for databases.
Creating an Elastic SQL Database Pool
Go to the new Azure portal and select the SQL Database Server on which you want to create a pool. One server can have multiple pools. But one database can be attached to only one pool. In the server blade click on the Add pool button.
Give a name to the pool. Select the pricing tier, and you can add databases to the pool at this time or later. Note the ‘Configure Performance Section’ and you can adjust the eDTU and the storage capacity for the pool. Also you can set the minimum and maximum eDTU usage per database. You can change these settings later. The number of databases per pool, the total number of eDTUs and the maximum size of the pool are determined by the pool’s pricing tier.
Managing the Elastic Database Pool
Now we have a pool and let’s see how to manage the databases in the pool. Managing the pool is done through the jobs, it requires certain installation in your azure subscription, which includes a cloud service, SQL Database, service bus and a storage account. You can click on the Manage or Create jobs button in the Elastic Pool blade, and if you haven’t set up the Jobs you will see the below screen for the first time. Jobs are in the preview stage and you should accept the preview terms, and also setup a credential. This credential will be used as the administrator credential for the Jobs SQL database.
After setting up the required resources for the jobs, now you can create jobs. Below screen shows the jobs creation blade. Jobs are scripted in TSQL, and note that here I have provided the credential of the SQL Server I want my script to run, not the credential of the Jobs SQL database.
I have the option to run the jobs immediately and also save them and run later. You can see the jobs in the Manage Jobs blade.
You can start a job by clicking Run and it will show real time updates about the job status.
All my databases are updated.
Elastic Database Pool is very convenient and a powerful approach to manage multiple databases as a group.
Elastic Database Pool Jobs is an application which is a hosted cloud service, which has a SQL database, a service bus and a storage account, these resources are charged separately in addition to the Elastic Database Pool cost.