October 21, 2014 at 10:35 am
HI,
I have configured a database mirroring between sql server 2008 and sql server 2014. Now when I try to do a manual failover from SSMS, the mirroring is going to a Paused state. I expected Mirror database will become principal and principal database will become Mirror. When I try to resume the mirroring from SSMS, Its not resuming. Can you help me in fixing this issue.
October 21, 2014 at 1:52 pm
Failing over from a previous version of SQL to a newer version of SQL is a one-way trip. You cannot failback from SQL 2014 to SQL 2008 since the database is upgraded once it becomes the principal on SQL 2014. The same concept applies to restoring databases between versions of SQL Server. You can go forward from 2008 to 2012 to 2014 but you cannot go backward from 2014 to 2012 to 2008.
This article explains in more detail:
http://msdn.microsoft.com/en-us/library/bb677181.aspx
Restrictions after you failover to an upgraded server instance.
After failing over from an earlier server instance to a SQL Server 2014 server instance, the database session is suspended. It cannot be resumed until the other partner has been upgraded. However, the principal server is still accepting connections and allowing data access and modifications on the principal database.
October 22, 2014 at 2:29 am
Additionally, the only time that mirroring is supported between different versions is as part of a rolling upgrade. To be honest it makes no sense any other time, because you can't fail back (because you can't restore, even log records, down-version) and hence a HA/DR solution where you can't fail over is a bit of a pointless solution.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
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