July 31, 2010 at 12:20 pm
Perry Whittle (7/31/2010)
the failover partner connection string parameter is only required if confuring automatic failover. You need to be using either the SQL native client or ADO.NET
Correct ... but ...
What else would be the purpose of a mirrored db, if you still lose time when you cannot afford it (i.e. at failover time) ?
Meaning if you would still have to adjust connection strings to the mirrored instance of your db.
IMO even without automatic failover ( topology with a witness ) one should prepare the whole stuff.
At least perform an impact analysis.
Also keep in mind that if you are using domain aliases to get to your instance, if you alter that alias, it may still take at least a couple of minutes before that gets replicated all over your domain controllers,...
So, if you can, roll out the correct middleware, so you can specify your failover partner data in your connections. This way, your apps will always connect if the database is available, at the primary instance or at the mirror instance.
Also keep in mind, you'll need to prepare your system jobs ( backup / dbcc checkdb / ... ) to be able to cope with the mirror db (which will be in "recovery" state).
Johan
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August 2, 2010 at 3:06 pm
ALZDBA (7/31/2010)
What else would be the purpose of a mirrored db, if you still lose time when you cannot afford it (i.e. at failover time) ?Meaning if you would still have to adjust connection strings to the mirrored instance of your db.
totally agree with you but just worth remembering that legacy apps that do not make use of the mentioned connection technologies, require manual intervention even though the database failover is automatic!
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August 3, 2010 at 1:05 am
Good point.
Those are the apps that should be documented in a failover checklist.
At least they should be mentioned in the migration/upgrade plan for the db.
Johan
Learn to play, play to learn !
Dont drive faster than your guardian angel can fly ...
but keeping both feet on the ground wont get you anywhere :w00t:
- How to post Performance Problems
- How to post data/code to get the best help[/url]
- How to prevent a sore throat after hours of presenting ppt
press F1 for solution, press shift+F1 for urgent solution 😀
Need a bit of Powershell? How about this
Who am I ? Sometimes this is me but most of the time this is me
August 3, 2010 at 3:45 am
Sudeepta,
I'm wondering if it's safe to open firewall ports to enable database mirroring. Even if you allow specific host, allowing it to traverse the Internet is quite scary.
How about create a VPN tunnel between the two data centers, let the network devices do the encryption and allow both SQL to mirror their databases natively without changing any ports? Wouldn't that be a safer approach? I am planning to do some database mirroring my self soon and I'm planning to run with this idea. I'll update everyone with the planning and execution.
Robert
August 5, 2010 at 4:49 am
Hello Robert,
I'm wondering if it's safe to open firewall ports to enable database mirroring. Even if you allow specific host, allowing it to traverse the Internet is quite scary. [
That's why it is suggested not to use the default database mirroring endpoint port, A custom port and a dedicated IP can be given access through firewall. Of course, your network and security team should be considered when implementing this, to meet the company policies.
How about create a VPN tunnel between the two data centers, let the network devices do the encryption and allow both SQL to mirror their databases natively without changing any ports? Wouldn't that be a safer approach?
To be honest, I haven't implemented it in this way till now. The encryption option is set during the endpoint creation. I don't think keeping the default port for the mirroring is wise, because, if we are talking about security, then that's the first point where an un-authorized person wants to look at.
I am planning to do some database mirroring my self soon and I'm planning to run with this idea. I'll update everyone with the planning and execution.
I would like to know, if you are successful in implementing the way you said earlier, I can be reached at sudeepta.ganguly@gmail.com.
Thanks & Regards,
Sudeepta.
http://twitter.com/skganguly
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