Database Mirroring Deprecated as of SQL Server 2012

By: on March 8, 2012 in AlwaysOn, Availability Groups, Database Mirroring, SQL Server 2012

Until now, Microsoft has not said much about the future of database mirroring post-SQL Server 2012. With the introduction of AlwaysOn availability groups, it didn’t make sense to have two very similar features over the long term. The RTM version of SQL Server 2012’s Books Online now confirms that database mirroring will be removed in a later version of SQL Server (see the section “Features Not Supported  in a Future Version of SQL Server” of the topic Deprecated Database Engine Features).

Before you push the panic button, remember that it will be at least two major versions of SQL Server before this happens, so you have time to plan your exit strategy for any database participating in a DBM pair. I’ll address this topic more as time goes on, but I felt this is an important change that should be pointed out.

12 Responses

  1. Marcos says:

    I don’t agree with Microsoft in that point, why deprecated Database Mirroring if AlwaysOn Availability Groups are not in Standard version of SQL Server 2012?

    Microsoft doing that, I suppose that in future releases AlwaysOn Availability Groups will be Available on Standard version.

    • Allan says:

      There is not 100% certainty that MS will add AG functionality to Std, but maybe they will. Like I said to Lee, it’s too soon to tell. For the why, you’ll have to ask MS. I had nothing to do with that decision.

  2. Lee says:

    So does that leave Std. Edition customers w/mirroring high-and-dry now?

    • Allan says:

      You’ve got failover clustering, log shipping, and if you count it, replication – all still supported. DBM is still in and supported until it goes away. Maybe MS will add some AG stuff to Std down the road. It’s too soon to tell – 2012 was just released.

  3. Lee Everest says:

    Right. Sort of immaterial though. There are probably thousands of customers who do not plan to upgrade to EE and who are not going to set up clustering. Now they have to do either one or the other to get the same benefit.

    This is, of course, a monitary decision; Microsoft does not make any money on editions than Enterprise, a fact. Unfortunately it isolates the medium-sized client into making a decision…go with a ‘poor-mans’ HA solution, or pay for a bunch of features that they may or may not use.

    • Allan says:

      Again, Microsoft may move some functionality to Standard in a future version. A good example of that is backup compression from 2008 to 2008 R2. Will they? I don’t have a crystal ball. Monetary decision or not, failover clustering is a viable option for instance level protection in Standard even today. You’d need a WSFC for AGs as well.

  4. Jon Reade says:

    Personally, I think Microsoft will alienate a lot of database shops that have come to rely on the simplicity and reliability that mirroring offers. AGs are a really nice feature, but I can’t see most DBAs willing to trade it for the alternatives if mirroring is deprecated, as they’re a pain to set up and maintain, by comparison. They’re in grave danger of loosing touch with everyone other than the big corporate DBA, just like Oracle have. And look what good it’s done them.

  5. Binu says:

    Always ON feature required clustering ?
    Then If mirror deprecated will affect Stand alone servers

  6. Clement says:

    Great Post!
    I do agree with the fact that removing mirroring is probably a monetary solution but it is not a good decision for MS because there are so many little boutique that uses mirroring! It works well even geographically.
    I have been on a geographic mirroring solution for a client for like 5 years and it works really well and it is really easy to handle. I never had runaway log, so easy.
    I am migrating now sql server 2008 R2 from them to 2014 and therefore to availability group and it is costing them a lot of more sytem engineering: many virtual ips, many AD interractions, file share witness, so on and so forth. It is quite good. However I think it was much much cheaper (even with entreprise) to set it up with mirroring.
    Those clients will now require a pretty damn good DBA and System engineer!
    I had many clients that lack of skills on setting up geographic AD and therefore I set them up with certificates for mirroring. They feel more relax with this….

    Oh well, maybe it is like the “nolock” deprecated feature that will never go away LOL

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