A SQL 2017 Licensing Question

  • Hi,

    We have three VM (V1, V2, V3) running on 3 separate host (H1, H2, H3). H1 has16 cores, H2 has 20 cores, H3 has 20 cores running on a remote data center.  We plan to setup AlwaysOn group V1 as the primary replica, V2 as readable secondary replica, V3 as log shipping secondary with all databases setup to nonrecovery mode. Also H3 only host V3, there is no other SQL instances installed on H3.

    If we buy SQL 2017 license on host H1, and H2, should we only pay 36 cores? If we buy software assurance, do we need to pay license for V3?

    Thanks,
    Lijun

  • Hi,
    no one can give you the correct answer. Please contact your sql server vendor to get the right  license for your sql server.
    Best regards,
    Andreas

  • Andreas, why is that? (not saying you are wrong, but am curious) one would have thought there must be a definitive formula, or way of comparing costs of licensing options?

    -- Alex

  • Anything you may get from people on the internet is simply opinion.  You need to contact Microsoft or your software provider for the definitive answer you seek.
    Even then you may get different answers depending on the individual you are talking to on this.

  • Despite all the warnings about talking to your licensing re-seller, and my own caveat that any advice I give must be checked with Microsoft, etc. the following is what I understand from the available documentation and how my clients have implemented this.
    As soon as you have 3 servers supporting the same production data, you will need to license at least two of the servers, based on the server with the most cores. Since H1 & H2 are in an AoHA relationship, with H2 a readable secondary, you can be pretty sure Microsoft will expect both these nodes to be licensed at the higher level (i.e. 20 + 20, not 20 + 16) even though one only has 16 cores and regardless of the presence of H3. Then H3 becomes your "free" DR server.
    This of course only applies if you have Software Assurance.

    This is a guide only as I am not a certified license re-seller and all advice must be checked with Microsoft.

    Leo
    Nothing in life is ever so complex that with a little effort it can't be made more complex (Including Microsoft SQL Server Licensing)

    Leo
    Nothing in life is ever so complicated that with a little work it can't be made more complicated.

  • As already mentioned, you definitely need your licenses to be covered with SA:
    "Microsoft permits License Mobility as an exclusive SA benefit available for all SQL Server editions."
    Although you still have some limited options to move your licenses between VMs without SA.

    If your V3 instance is entirely passive, no users connect to it, and used only for purposes of AlwaysOn, then this applies:
    "For each server licensed with SQL Server 2017 and covered by active SA, customers can run up to the same number of passive failover instances in a separate, OSE to support failover events."
    Source:
        sql_server_2017_licensing_guide.pdf
        http://download.microsoft.com/download/7/8/c/78cdf005-97c1-4129-926b-ce4a6fe92cf5/sql_server_2017_licensing_guide.pdf
    Which means you need to license V1 and V2, total 36 cores; V3 is considered passive. There is the possibility that V3 is considered a passive instance of V1 in isolation, meaning V3 should only have 16 cores. But if you are fully licensing both V1 and V2 as part of your DR, I don't think this would be contentious (yep, that is my opinion 🙂

    One further note; I don't know what your disaster-recovery plan is, but bear in mind:
    "In the event that a passive instance of SQL Server becomes active for any reason, the primary SQL Server 2017 license is dynamically reassigned to the newly active server via the License Mobility within Server Farms SA Benefit, and now assumes all active workloads."
    So, if your 16-core H1 dies, and is replaced with your 20-core H2 then all is fine (as both H1 and H2 are licensed). But if your 16-core H1 is replaced with your 20-core H3 (which is not licensed) for longer than an emergency period of time, then you'll need to purchase additional licenses.

    My experience with Microsoft is, you explain to them how you intend to license your infrastructure, and they say yes that's fine. If you ask them how to license your infra, you'll get 5 different opinions from 5 different resellers. Finding a good reseller is definitely worth it.
    There are other possible scenarios, such as Enterprise vs. Standard, and "Licensing for maximum virtualization", which you might want to investigate.

    Andy

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