If you have it available SAN replication is often VERY VERY good at DR/HA solutions. I would absolutely recommend AGAINST DoubleTake. I'd rather take a hot poker in the eye, TWICE than ever deal with that again.. However SAN replication is often not available to smaller organizations. I have had a fair amount of experience with MS clustering and have largely enjoyed it. Both active/passive and active/active. I just wish that it allowed for load balancing on top of the same database files, that I think Oracle does. That would probably be my one complaint.

I would ask what scenarios you are trying to protect against and what the requirements that you need to meet. And they need to be specific, not like, "the database just needs to be available". How long can it be down? Do you need off-site replication? Do you have a BCP site. What other tech do you have available, like SAN replication and such. DR/HA solutions are rarely done solely by the DBA staff. But designed by subject matter experts such as server, storage, network, AND database in your organziation. Sometimes a couple of these people are the same person, in bigger orgs not so much..

CEWII