SQL Server 2008数据库镜像

Question

I have a little problem with the database connection. There are 2 database server:

DBSA, DBSB

DBSA (primary server)
DBSB (mirrored server)

I connect with the following Connection String :

Data Source=DBSA;Failover Partner=DBSB;Persist Security Info=True;Initial Catalog=database;User ID=user;Password=password

When I run my program on my PC it works, but when I try the program on the web server in the DMZ the failover doesn't work.

Does somebody knows the reason for this?

=> I forgot to tell in the question. There is also a witness server.

Answer 1

The app must be getting the failover server name from the SQL server (probably not even the FQDN name) instead of the connection string in the web.config .

Try running ipconfig /flushdns then failover the SQL database and after you get the first SQL exception error run ipconfig /displaydns to see which name it cannot resolve. My bet is it doesn't look anything like the DB alias you have set up in the connection string for failover partner...

I had to deal with the same thing - Microsoft's implementation is a little convoluted since they're trying to cover every possible scenario.

Answer 2

Run this on your principal db

SELECT DB_NAME(database_id) AS 'DatabaseName'
, mirroring_role_desc 
, mirroring_safety_level_desc 
, mirroring_state_desc 
, mirroring_partner_instance
FROM
sys.database_mirroring WHERE mirroring_guid IS NOT NULL; 

The value returned in mirroring_partner_instance is the server name that will be used by your connection for failover, not what you specify in the config. I imagine your PC can see this server using this name, where as when running in the DMZ it cannot.