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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.