Azure SQL Database Scalability – Will Scaling Make My Website Go Down?

azure-sql-databasescalability

I have a website using Azure SQL databases, and I have some questions:

  1. How does the scaling process work? Is there a flow, diagram that illustrates it?
  2. Will the scaling cause any downtime in my website?
  3. Am I able to write things to the database during the scaling process?

Best Answer

  1. How does the scaling process work? Is there a flow, diagram that illustrates it? See this link: https://docs.microsoft.com/en-us/azure/sql-database/sql-database-service-tiers
  2. Will the scaling cause any downtime in my website?

No new connections for a brief period and existing connections might rollback.

Changing the service tier and/or performance level of a database creates a replica of the original database at the new performance level, and then switches connections over to the replica. No data is lost during this process but during the brief moment when we switch over to the replica, connections to the database are disabled, so some transactions in flight may be rolled back. This window varies, but is on average under 4 seconds, and in more than 99% of cases is less than 30 seconds. If there are large numbers of transactions in flight at the moment connections are disabled, this window may be longer.

  1. Am I able to write things to the database during the scaling process?

Yes but you might see your transaction is rolled back.

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