We have a SQL2012 mirroring with a witness, all on 3 seperate servers. Auotmatic failover is enabled, connections strings are properly filled. SQL Browser is running. For some reason, one webservice is *sometimes* "ignoring" the principal server and tries to connect to the mirrored database, resulting in a "Failed to open the explicitly specified database". This is always the case when a where webpool is recycled, but also on other different times. On this webserver is the witness also running. The witness is SQL2012Express. Any ideas how to fix this issue?
Make sure that the mirrors are always listed in the same order in the configurations and check that network connectivity is entirely stable. If the webservice is trying the Mirror then I would say that most likely it's not "seeing" the Principal and tries the fallback entry. Check the Windows logs or with the network team. On a pool recycle it sounds more like a mis-ordered configuration and it's trying the Mirror first.
Hi, first try to find out why the web service fail? the best tool is Fiddler web proxy which catch all service request and response from IIS or any other application server, you can take a look to header and body of service call, Which kind of web service do you use ? How much is the size of the data in web service call back ? Also enable your application server logs, Can you post the error message?