Right now we tried to create a new way to DR that when we are doing large deployment, the DB still up and running.
May I know if SQL 2008 (not R2) mirror can help when we are trying to upgrade the SQL 2008 server from SP1 to SP2 (for example), or upgrade the Windows the SQL server installed on top from Windows 2008 R2 to Windows 2008 R2 SP1:
1) keep the connection from application while the DB is switching over to DR site.
2) Upgrade one of the DB first (primary or DR DB),
3) Once it is verify working good, then we switch over to DR DB to keep operation.
4) then we upgrade the primary DB and verify it is working good.
5) we bring the primary DB server as a primary again and leave the DR DB as usual.
6) upgrade done.