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Posts Tagged ‘Replication’

Probable Double Take 7 bug during the failover of SQL Server 2005, 2008 or 2008 R2!

February 4, 2014 Leave a comment

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Hi again!

I am working currently on a replication project using the famous Double Take to replicate SQL Server 2000/2005 databases and file shares between two remote sites.

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I have some experience with The Storage Mirroring (Double Take) 5.3 from HP and I liked really its different consoles. As we have not the necessary licence for Entreprise Edition, we were obliged to use the new Double Take 7.0 delivered by Vision Solutions. And unfortunatly my expectations were not met.

Unlike Storage Mirroring 5.3, when configuring a SQL replication job, there is no manner to configure the SQL services to start during the failover process. I have searched for a file in the Double Take repository that contains the services to start but no way!

SQLDT

And the final result when you launch your failover process, the job fails! Just take a look on the job log to find the cause : the SQLSERVERAdHelper service cannot be started!

This service is just launched when an SQL Server object needs to be created in the Active Directory to register an instance of SQL Server and is configured to start manually. So the only way to start the MSQLSERVERADHELPER is from SQL Server.

But our famous Double Take fails when starting this service! And this is very logical!

What is the solution? If this SQLSERVERAdHelper service is not so crucial for you, you can delete it! Yes this solution was applied in our case using this command : sc delete MSSQLServerADHelper.

By doing so, the failover process worked for us finally!

NB: the MSSQLSERVERAdHelper service is removed from SQL Server 2012 and later (I suppose). So, no problem when replicating with Double Take 7.0.

Advanced Hyper-V replication configuration

August 9, 2013 Leave a comment

Hi,

In the last post, I presented the Capacity Planner for Hyper-V Replica and in the documentation, I discovered that this tool can suggest a value for the parallel machines number to be transferred.

Rapidly, I asked Google about this parameter and bingo! A very nice article from Microsoft that describes more parameters to configure :

  • DisableCertRevocationCheck
  • MaximumActiveTransfers
  • ApplyVHDLimit
  • ApplyVMLimit
  • ApplyChangeReplicaDiskThrottle

All these parameters can be configured through the registry.

Enjoy!