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We have a SP2010 enterprise farm. Currently it is using SQL2008R2 with clustering and we planned to add DR on the farm. Due to some technical restriction, we cannot move the 2nd sql server to DR datacenter and keep the clustering.

So we decide to remove clustering and use mirroring instead. We do not have budget for additional witness server.

I have went though this Microsoft article Configure availability by using SQL Server database mirroring (SharePoint Server 2010). It seems SharePoint 2010 is well designed to support mirroring. But I fail to find any reference about mirroring without witness.

Could you please advise what would be the procedure? Without witness can SharePoint aware the primary SQL is down and switch to secondary?

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I did not clearly get what you are trying to achieve. You have to distinguish between HighAvailability (HA) and DesasterRecovery (DR).

Important word in advance: Not SharePoint decides to bring databases on another Server online. You need to get SQL-Server it's job done correctly and SharePoint will rely on that.

  • Your already implemented cluster-setup is only a HA solution. HA must provide automatic failover mechanisms, so you do not need to intervention manually in case of an error.
  • Database Mirroring can act as HA or DR, depending on your configuration. HA only works with a witness, because it is required for an Automatic Failover. Without a witness you get DR, because it requires you to do a manual failover.
  • You could leave your existing Cluster-Instance to achieve HA. In my opinion it is the better HA-solution compared to Mirroring. Then you can add a mirroring-session to that cluster to get DR.
  • In SharePoint I can configure "Failover server" for each database. Should I configure it and what is the procedure to tell SharePoint "ok, time to switch"? – Mark L May 26 '17 at 7:06
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    Yes, you have to configure the "Failover server" if you use database mirroring. But the decision "ok, time to switch" is not done by SharePoint. SQL-Server decides and takes the databases only on one side online. SharePoint only asks "Which side is online?" and then makes use of it. – MHeld May 26 '17 at 8:00
  • I was told by DBA SQL2008 do not support "mirroring-session" on cluster. We have to upgrade to 2012 at least. – Mark L May 26 '17 at 9:22
  • I've never set this up in 2008R2, but this linked article has no version limitation: docs.microsoft.com/en-us/sql/database-engine/database-mirroring/…. There have also been no changes on mirroring from 2008R2 to 2012, because it's a deprecated feature since 2012. Did your DBA mix up mirroring with AlwaysOn Availability-Groups (AGs)? They where introduced in SQL2012 and you can also build AGs on top of a cluster. – MHeld May 26 '17 at 10:01
  • Hi @MHeld , sorry to bring up old topic. We performed a failover test with DB mirroring. We setup sql01 and sql02 mirrored. After we shutdown sql01, after 15 minutes, it seems nothing is switched. CA is returning error. So I setup SQL alias on app server (sql01 > sql02) then everything is working. Do you think witness server is essential? Or all I need is to reboot all app servers? – Mark L Dec 27 '17 at 6:17

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