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SQL Server: Fail-Over Rights versus “Cold” Disaster Recovery Rights.

  • Article

By: Lacey Hartje

Summary: What’s the difference, aren’t they both for disaster recovery? Aren’t they the same thing? Fail-over Rights and “Cold” Disaster Recovery Rights serve 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 will need DR for your mission critical business processes, but you don’t fully understand the differences between Fail-over Rights and “Cold” Disaster Recovery Rights.  Don’t worry! We’ve prepared a comparison for you to help you decide which DR scenario is right for you and your business.

 

Fail-over versus “Cold” Disaster Recovery Rights Summary.

Fail-over Rights

“Cold” Disaster Recovery Rights

Is this a Software Assurance Benefit?

No, but consider SA for maximum benefit

Yes

If I purchase SQL Server under the Server/CAL licensing model, do I need SA for my CALs in order to receive this right

No

Yes

Is the customer deemed Complimentary Licenses for the backup server?

No

Yes

Does this right require applying new or moving existing licenses to the backup server?

Yes

No

The backup server is normally turned…

On/Passive

Off/Cold

Does 90 day short-term reassignment apply?

Yes

No

May the backup server be in the same cluster as production server?

Yes

No

Can I run the backup and production servers at the same time?

No

Yes, only for software self-testing, patch management and during recovery

 

Explanation:

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.   If you are licensing SQL Server 2012 per Cores and the OSE in which you use the passive fail-over Running Instances is on a separate server, the number of Physical/Virtual Cores on the separate server must not exceed the number of Physical/Virtual Cores on the Licensed Server and the Core Factor for the Physical Processors in that server must be the same or lower than the Core Factor of the Physical Processors of the Licensed Server.  To summarize, the fail-over cannot otherwise have a higher/larger licensing requirement than the primary/active server. 

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 hardware - you will need to move the SQL licenses or 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).  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 (moved to another server) 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 move the licenses to a fail-over server.  To not be 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.  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.

“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.

 

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.

Comments

  • Anonymous
    March 29, 2013
    is there any time limitation on Fail-Over between licensed server and passive server?

  • Anonymous
    April 11, 2013
    @Khalid - Yes, there is a time limit based on the 90 day reassignment rule (e.g. you cannot reassign a license from one server to another more frequently than 90 days).  As covered above, you must reassign your license from your failed active server to the once passive/now active server as soon as the passive server becomes active.  If you have SA coverage, the 90 day reassignment limit does not apply due to License Mobility.  If you do not have SA coverage, you cannot reassign the license back to the original server sooner than 90 days. You may find the SQL Server 2012 Licensing Guide helpful.  Take a look at the second half of page 15. download.microsoft.com/.../SQL_Server_2012_Licensing_Reference_Guide.pdf

  • Anonymous
    August 15, 2013
    Without SA, what are the licensing implications from restarting the primary due to OS or SQL patches (therefore causing a failover), would you then have to stay on the secondary server for 90 days? Also, following a DR event where everything has been failed over to the secondary node; you fail back to the primary after 90 days, but then for 90 days after that, any fail over event (including unplanned DR) would violate the license?

  • Anonymous
    February 05, 2014
    In the table, for Fail over, you say "The backup server is normally turned…On/Passive". But then below that you say "Can I run the backup and production servers at the same time? .... No". How can these both be true (as Production will normally be running) ? Is it OK to run both concurrently as long as the Passive server is doing no production work ?

  • Anonymous
    February 18, 2014
    Two Active - Active nodes with db instances on each. In this scenario there are two db instances on one node and three on the other node. We are Enterprise core licensing both nodes with L. But; do I need SA for moving these db instances between those two nodes? Thanks

  • Anonymous
    August 05, 2014
    The comment has been removed

  • Anonymous
    October 09, 2014
    Unfortunately it's no more the case for SQL2014 now - failover rights require SA coverage. we learned it by the hard way and we are trapped now.

  • Anonymous
    August 27, 2015
    Hi!
    I have been trying to follow the literature on SQL core licensing but it’s 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 purpose.
    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 be fully licensed also?

  • Anonymous
    January 13, 2016
    Chris, you would need 2 Licenses for you Primary Server (1 license per 4 cores) with Software Assurance, to cover your secondary DR server, as long as all you are doing is passive DB migration, and no actual workloads are coming from the secondary server