Hello, I tried this and it doesnt work, I just started up the service with -T flag on default instance but I havent been able to start it with -T flag 1400 on named instances.
How can I Know that the directory MSSQL.4 is the MIRROR instance
C:\Archivos de programa\Microsoft SQL Server\MSSQL.4\MSSQL\Binn>sqlservr.exe -T
1400 MIRROR
I tried LUCHO\MIRROR, MSSQLSERVER$MIRROR
and It doesnt work
Thanks
Another question I have, in the documentation it says that mirroring is only for evaluation purposes and not for production environments, what does it suppose to mean MSFT didnt test the mirroring feature enough If its not suppoerted why its included..
Microsoft support policies do not apply to the database mirroring feature in SQL Server 2005. Database mirroring is currently disabled by default, but may be enabled for evaluation purposes only by using trace flag 1400 as a startup parameter. (For more information about trace flags, see Trace Flags (Transact-SQL).) Database mirroring should not be used in production environments, and Microsoft support services will not support databases or applications that use database mirroring. Database mirroring documentation is included in SQL Server 2005 for evaluation purposes only, and the Documentation Policy for SQL Server 2005 Support and Upgrade does not apply to the database mirroring documentation.

-T 1400 doesnt work on named instances
Ashraf Hameeda T
Couple of things:
1) Looks like you're trying to start the database engine from the command line...to do this, part of your command line needs to include some additional options, particularly in this case the '-s' option to specify a named instance. See the topic 'Using the SQL Server Service Startup Options' in BOL for assistance with this.
2) You probably want to be starting the instance using the service control manager instead of the command line. You can specify command line options and other things there as well, including trace flag options. Open the SQL Server Configuration Manager (from SQL Server 2005 Start Menu group), right click on the appropriate instance in the list, then navigate to the Advanced tab. Here you can specify things like command line options. See the topic 'SQL Server Configuration Manager' in BOL for help here.
3) Database mirroring is for evaluation purposed only in the RTM release of SQL 2005, and fully supported in the SP1 released recently. If you apply SP1, you're fully supported. As for why it wasn't supported in RTM, just simply wasn't ready for whatever reasons.
4) The trace flag definately works fine with named instances...
HTH,