Database Mirroring and RTC Client Redirection

knm

Hi,

When implementing a Database Mirroring for NAV2009R2 NA using SQL Server 2008, how can I configure RTC so that it will redirect the client access from Primary server to the Secondary server, when a failover occurs.

According to the KB article that I found on MS, it says that it is not possible to accomplish a "transparent client redirection", but it does say that "The ODBC driver does let you specify a failover partner server name."
http://support.microsoft.com/kb/937005

I'm trying to find out how I can set the failover partner server name, like mentioned above, and how it is not "transparent", even if you can setup a failover server name.

Thank you.

bbrown

The RTC client connect to the service tier, not the database. So database mirrroring is sort of irrelevant. It's the service tier that you'd need to redirect. As far as I know, it doesn't.

knm

bbrown,

Sorry, you're right about the Service tier, and sorry for the lack of details.
But assuming that Service Tier is hosted on the same Server that is hosting the Database (for both Primary and Secondary servers), if Primary server goes down, then the Service Tier for the Primary server will also go down together.

So it comes down that RTC client has to redirect its reference to the Service Tier, so that it will look for the Service Tier hosted on the Secondary Server.

Do you think a redirection is possible for this?

bbrown

First, why would you run the service tier on the same server? SQL should be a dedicated system. And so should the service tiers.

But that point aside. I've had a number of discussion with the Technical Advisory group (or whatever they are now called) on the subject of high availaibility. The bottom line is nothing is officially supported. They're not saying that specific solutions won't work. But since they've not done any testing, they won't take an official postion.

To answer your question, no I don't think it would work.

What are you trying to accomplish? Are you sure mirroring is the right solution? If redirection is an issue, why not clustering? The redirection issue then might go away. Of course, any solution you choose you should plan to prototype. The worse thing you can do is assume how an HA solution will behave. Then discover you were wrong during a real incident.

knm

bbrown,

Thanks for your feedback.
The reason why I'm not dedicating a server for the service tier is just from cutting down on cost.

I'll plan and work through prototypes to come up with a final decision.

Regards,

bbrown

IMHO, if you can't manage the budget for a service tier machine, you're in no position to be contemplating HA environments. Is a decent sevice tier machine really goign to break your budget?

bbrown

BTW - Mirroring goes away in the next release of SQL.