Database redunancy

I have been asked to investigate the possability of setting up a fault-tolerant Oracle instance on a Sun 450/SunOS5.6 system. The requirements are somewhat fuzzy, but maybe someone will recognize what I'm trying to accomplish.

The system architects want to set up the file system so that it is mirrored to another file system. They would like to have Oracle set up so that if the primary database fails that another instance will be instantly available which uses the mirrored files.

In a way this seems to be backwards from parallel server since that schema would use two different instances against the same files. In my case it would be an instance with the same name as the primary instance except that it would be running on another machine (in a cluster configuration).

I do see some tremendous problems with this since all of the applications programs are actually running on NT workstations as client applications. Even if I could do the database end I don't see how I could instantly switch users over to the alternate instance without diddling with the tnsnames.ora. If it were simply a matter of having them log in different by specifying a difference database alias I could see how that could be handled, but I didn't write the login screens and the database alias is hardcoded into one of the programs and is handled by a global configurator for the other applications. Considering that the current usages is about 80-100 call-center agents, it would appear to me that the deck is stacked against me for any type of automated switchover.

So, that is the background. Any thoughts? Received on Thu Dec 23 1999 - 07:37:15 CST