November 19, 2008 at 8:32 pm
I'm trying to setup database mirroring using SQL2005 SP2 Standard Edition. This Edition doesn't allow us to use High Performance Mode, but it doesn't matter to me.
So, I'm using High Safety without automatic failover (synchronous mode). It means the principal doesn't commit its data until it receives confirmation from the mirror that the data in question was commited succesfully on the mirrored database.
I want to test that statement. In my imagination this concept is equal with Oracle Data Guard Synchronous Mode: every time user hits Save in his application, he must wait until both the principal and the mirror complete saving the data. If the network must undertake a long physical distance or a complicated journey to get the data from the principal to the mirror, that poor user will sit and wait and wait and wait and .. well, you get the idea.
But disregard its shortage, this mode has its superiority: make sure our data always has a protection. Some businesses has an opinion: it's wiser to stop entering data than to continue without a mirror.
But, after walking several test I confused with the result: a user still can entering data in his application although I shutdown the mirror. In my imagination if principal and mirror out of sync then the user application will halt, he can't save or commit his work because like I said before, bosses and executive have an opinion: it's wiser to stop entering data than to continue without a mirror.
I'm using TOAD for SQL Server v4.0 as client application. After shutdown Mirror, I'm entering data and save my works onto Principal. I closed TOAD and reopen the database, my last data still there, not lost.
I think there is a method to change this behavior to be what I expected.
But How ? I googling several days without solution. Maybe you can give me a solution for this. I Need advice from you guys.
best regards,
gunawan
indonesia
November 23, 2008 at 4:30 pm
If the mirror is unavailable then the principal will continue to run if you are not using a witness ... you can set up alerts to notify you when this occurs. If you want to stop the principal when the mirror becomes unavailable then you should set up a witness then disconnect it - a quorum can never be formed so no failover can take place.
November 25, 2008 at 9:44 pm
I'm sorry for the late response. I'm trying to setup high availability mode using witness but failed.
Without witness, the database mirror running well using high safety without automatic failover.
Using SQL Server Management Studio and Mirror Wizard I get an error message like this:
"The Alter Database command could not be sent to the remote server instance 'TCP://witness.testcluster.local:5022', The database mirroring configuration was not changed. Verify that the server is connected, and try again (Microsoft SQL Server, Error: 1456)"
Principal is SQL Server Standard Edition SP2
Mirror is SQL Server Standard Edition SP2
Witness is SQL Express SP2
Still fighting to resolve the problem 2 days long without progress.
Searching in Google........
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