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Does SQL Azure require a compute instance? RRS feed

  • Question

  • Assume that I want a Web Role running on 2 instances, a Worker Role running only 1 instance (not mission critical), and also a 30GB SQL Azure database. Do I need to pay for additional compute instance(s) to run the SQL Azure, or is the compute instance for that already included? If included, how powerful is it?

    Basically, I can clearly see that there are different sizes of VM available for me to scale out my Web and Worker Roles as I see fit. How do I (or do I) get to decide how much power my SQL Azure instance has at its disposal? If it does not use a compute instance which I can manage, what happens when the controller updates my instance, such as patching the OS? I was told that, if I have 2 instances powering my Web Role, my uptime will be assured, because the controller would only patch one OS at a time, leaving the other one running. How does this apply on the SQL Azure side?

    If a compute instance is required, do I need 2 or more of them to power the SQL Azure? I understand that if I order 2 databases, they are separate databases and I may implement sharding if I see fit, but either way, they are wholly separate databases. That is fine. My question is, where does SQL Azure get its compute power?

    Thanks!

    Monday, May 2, 2011 6:22 PM

Answers

  • -- Do I need to pay for additional compute instance(s) to run the SQL Azure, or is the compute instance for that already included? If included, how powerful is it?

    No. A SQL Azure database comes with its own compute so you do not pay extra for it. There are no published performance figures. However, SQL Azure is a multi-tenant system so compute is shared with other tenant. SQL Azure implements throttling to alleviate the hogging of compute by one tenant. This throttling is made visible by a connection being dropped. This is described in the Connection Constraints section of this MSDN page.

    --  I was told that, if I have 2 instances powering my Web Role, my uptime will be assured, because the controller would only patch one OS at a time, leaving the other one running. How does this apply on the SQL Azure side?

    There is currently no way to specify a reserved amount of compute in SQL Azure. You can reserve storage by choosing a different database size. To provide high-availability, SQL Azure maintains a primary and two backup copies of each SQL Azure database. If a problem is detected with the primary copy or the server it is running on becomes too hot, SQL Azure atutomatically promotes one of the secondary databases to the be primary.

    -- My question is, where does SQL Azure get its compute power?

    SQL Azure provides its own compute power that you get as part of the payment for a SQL Azure database.

    • Proposed as answer by Marc Loeb Monday, May 2, 2011 6:47 PM
    • Marked as answer by cardplayer158 Monday, May 2, 2011 7:10 PM
    Monday, May 2, 2011 6:35 PM
    Answerer

All replies

  • -- Do I need to pay for additional compute instance(s) to run the SQL Azure, or is the compute instance for that already included? If included, how powerful is it?

    No. A SQL Azure database comes with its own compute so you do not pay extra for it. There are no published performance figures. However, SQL Azure is a multi-tenant system so compute is shared with other tenant. SQL Azure implements throttling to alleviate the hogging of compute by one tenant. This throttling is made visible by a connection being dropped. This is described in the Connection Constraints section of this MSDN page.

    --  I was told that, if I have 2 instances powering my Web Role, my uptime will be assured, because the controller would only patch one OS at a time, leaving the other one running. How does this apply on the SQL Azure side?

    There is currently no way to specify a reserved amount of compute in SQL Azure. You can reserve storage by choosing a different database size. To provide high-availability, SQL Azure maintains a primary and two backup copies of each SQL Azure database. If a problem is detected with the primary copy or the server it is running on becomes too hot, SQL Azure atutomatically promotes one of the secondary databases to the be primary.

    -- My question is, where does SQL Azure get its compute power?

    SQL Azure provides its own compute power that you get as part of the payment for a SQL Azure database.

    • Proposed as answer by Marc Loeb Monday, May 2, 2011 6:47 PM
    • Marked as answer by cardplayer158 Monday, May 2, 2011 7:10 PM
    Monday, May 2, 2011 6:35 PM
    Answerer
  • This is a beautiful, complete answer.

    Thank you very much.

    Monday, May 2, 2011 6:41 PM