Licensing How To: SQL Server Fail-Over vs. Cold Disaster Recovery Rights.

The Licensing How To series posts are provided by our Customer Service Presales and Licensing team members.  These scenario based licensing topics are written on trending topics and issues based on their interactions with customers, Partners and field sellers.  For more posts from the Licensing How To series, search the “Licensing How To” tag on this blog.

Summary: What’s the difference, aren’t they both for disaster recovery? Fail-over Rights and “Cold” Disaster Recovery Rights offer two different, but similar purposes. For SQL Server “Cold” Disaster Recovery (DR) Rights are a Software Assurance (SA) Benefit while Fail-over Rights do not require SA coverage, but to get the maximum benefit of Fail-over Rights you will want to consider SA coverage for your SQL Server licenses.

Scenario: Your department is implementing a SQL Server solution and you need a disaster recovery (DR) solution for your mission critical business processes but you don’t fully understand the differences between Fail-over Rights and “Cold” Disaster Recovery Rights.  We’ve prepared a comparison table to help you decide which DR licensing right may work for you and your business.



(click table for larger view)


Fail-over Rights for Microsoft SQL Server do not require Software Assurance (SA) coverage.  For any Operating System Environment (OSE) in which you are running instances of SQL Server you may use up to the same number of “passive fail-over” Running Instances in a separate OSE on ANY Server for temporary support.  You may run the passive fail-over instances on a server other than the licensed server. A passive SQL Server instance is one that is not serving SQL Server data to clients or running active SQL Server workloads.

Take note: Special requirements if you are licensed for SQL Server 2012 per Core. 

Here is where it gets interesting.  You do not require SA for SQL Server Fail-over Rights, but once you activate the Passive Fail-Over server in a DR then that Passive Fail-over becomes the active server (during a fail-over event) and it must be fully licensed for SQL Server.  You can accomplish this by assigning new licenses to the (now active) passive server, or by reassigning existing licenses from the primary server to the backup server once the instances of SQL Server on the primary server are inactive and no longer performing SQL Server workloads.

Next you must consider what happens when you want to move your workload away from the formerly passive now active DR server to the original physical server/host - you will need to move the SQL licenses (e.g. reassign them). 

The basic rule of license reassignment is that most, but not all, licenses may be reassigned from one device to another, but not on a short-term basis (meaning not within 90 days of the last reassignment, except when the licensed server is retired due to permanent hardware failure).  This short-term basis rule applies to SQL Server 2012.  What this means is that your SQL Server 2012 licenses without SA may only be reassigned once every 90 days.  This may not fit your fail-over strategy very well.  If you can live with the passive server being your active server for the next 90 days, you need no further licensing.  However, if you have another fail-over event within 90 days you may not reassign or move the licenses to a fail-over server, thus rendering your fail over rights unusable during the 90 days after the last fail over event. 

To avoid being bound by the 90 day short-term reassignment rule you would require License Mobility within Server Farms which for SQL Server 2012, requires active SA coverage.  With SA coverage, you can fail over (then back) between your primary licensed server and fail over server as often as needed, without regard to the 90 day limit.  The bottom line is - to get the maximum benefit of SQL Server 2012 Fail-over Rights you require active SA coverage.

Fail-Over Rights are described in the Product Use Rights (PUR) and are listed in the Additional Terms section for the SQL Server editions.  A more complete explanation of Fail-over Rights is included in the Microsoft SQL Server 2012 Licensing Guide.  As of the time this post was published, passive fail over rights are unique to SQL Server and no other server products have this use right.

“Cold” Disaster Recovery Rights are a Software Assurance (SA) Benefit for qualified server licenses which includes SQL Server.  Customers with active SA on their SQL Server licenses and related CALs (if licensed via the Server/CAL licensing model) are eligible for complementary server licenses for disaster recovery purposes.

For each qualifying license the customer has enrolled in SA including all related CALs (if required by the product and licensing model), the customer will be deemed to have a second (complementary) server license with which they may deploy the same product on a “cold” back-up server solely for Disaster Recovery (DR) purposes. This benefit expires with the customer’s SA coverage.

The “Cold” Disaster Recovery Server must meet the following requirements:

  • The server must be turned off except for limited software self-testing and patch management, or disaster recovery. (customers
    who are virtualizing must keep the physical host server powered down)
  • The DR server may not be in the same cluster as the production server.
  • You may run the backup and production instances at the same time only while recovering the production instance from a disaster.
  • Your right to run the DR instance ends when your SA coverage ends.

“Cold” Disaster Recovery Rights are explained in both the Product Use Rights (PUR) (Appendix 2: Software Assurance Benefits) and the Product List (Section 7 – Software Assurance (SA) Benefits and Online Services (OLS) Benefits.  Of course, since the Cold DR Rights require that your server be physically powered down most all the time – this may not always be the best option in a database solution.  It does however, provide a good option for customers who want to reduce the time needed to redeploy a failed server (e.g. in the event of disaster, you can simply power on a pre-installed and pre-configured server).  Unlike passive fail over rights, Cold DR Rights apply to any server products with active SA on the server(s) and CALs.

This is one scenario, and licensing situation. Each customer scenario can vary by deployment, usage, product version, and product use rights.  Always check your contract, and the
current Products Use Rights document to confirm how your environment should be fully licensed.  The blogging team does not warrant that this scenario will be the right licensing solution for other similar cases.




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  6. Anonymous says:

    The two extracts below from the October 2013 Product Use Rights and October 2013 Product List confirm that under "Failover Rights" even when the "passive" server "kicks-in", you do NOT require reassignment of licenses (or the acquisition of new licenses), so long as the "passive instance" is only being used temporarily whilst the active server is "repaired". The nature of Active/Passive is that the Passive will become Active in circumstances where the Active Server has failed. The intention of Failover Rights was always (and still is) to grant the usage of the second instance permenantly as a passive instance and also temporarily as an active instance, without having to acquire additional or reassign existing licenses.

    Product Use Rights Extract: "For any OSE in which you use Running Instances of the server software, you may use up to the same number of passive fail-over Running Instances in a separate OSE on any Server for temporary support."

    Product List Extract: "You may run the backup and production instances at the same time only while recovering the production instance from a disaster."

  7. jerry says:

    So can you consider the 2nd server “Fail-over Rights” passive server if you are log shipping to it from the primary server?

  8. Dale Offret says:


    The SQL Server 2012 Licensing Reference Guide, on page 14 says, “Log shipping and database mirroring take place at the database level, whereas failover clustering takes place
    at the SQL Server instance level.”

    You would not be able to do log shipping to a passive instance. Your replication in a fail-over rights environment would need to be done outside the scope of log shipping or db mirroring.

  9. james says:

    So, on my SQL Server, we have a line of business application. We use Core based licensing for SQL. In the case of a disaster taking out our primary site, I don’t want to have to reinstall the LOB or any patches, so I have Veeam replicating my VM offsite for quick DR purposes. If there is a disaster, I just power on the VM. What scenario does this fall under? What licenses am I required to have?

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  12. Angela Militino says:


    Thanks! Well done! Is it the same in SQL 2014?

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  15. Ed says:

    Can you update the article for SQL 2014, now passive replica is an SA benefit….

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  17. Chad says:

    Without an active SA, how many licenses are required to run SQL2012 in an active/passive 2-node cluster where each node is identical to the other and has 8 cores (two quad core CPUs) each, for example? Also how does this affect failover for the instance
    if configured as a WFCI? Can the instance failover and failback as many times as needed between node-1 and node-2 as long as the cluster always runs SQL2012 actively only on one node at a time always idling the other node?

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  20. Chris says:

    I have been trying to follow the literature on SQL core licensing but its so confusing.
    Issue: I want to license my primary server (has 2 processors and each processor has 8 physical cores, while the server is Hyper-thread) with MS SQL Core 2014 and also equip my other 2 physical servers (having the same specs) with the SQL for disaster recovery
    Question: How many licenses do i require for the primary server and what is the cost effective way of licensing the disaster recovery servers taking into consideration Software Assurance or do they have to have licenses also?

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  26. GB says:

    Dear Team,

    I have a Licensing Query on SQL Server 2014. I have a VMWare Cluster with 8 hosts and I have installed SQL on one of the VM’s which is a cluster to the other node as Passive Server.

    Do I need to license on the SQL VM’s which is a cluster all across the 8 hosts. However at a given point of time only one is active.

    Please advice?

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