Migrating 9i(24x7) on Linux to Solaris

Question

Hello,
What would be the best method to migrate a 9i, 24x7, 30gigs database on Linux to Solaris without shutting down the database and without losing any data during and after the move. Thank you in advance.

Answer 1

You're going to have to have some downtime in order to move from one system to the other. It is possible, though it will probably be quite labor intensive, to make this downtime very small. The question, then, becomes how much effort you're willing to expend to minimize downtime.
You could create a new database on the Solaris machine and configure replication from the Linux box to the Solaris box. This probably involves creating a bunch of materialized view logs on the Linux box, which will tend to increase the load there. Depending on the volume of changes happening in a given period of time, it may take some time for the Solaris box to get close enough to the Linux box that you can shut off the Linux box, finish replicating the data, and open the Solaris database for transactions.
Of course, every client will have to be pointed at the new database rather than the old database during this transition. Exactly how this is done will depend on your precise environment. Ideally, it would be as simple as updating an Oracle Internet Directory entry or a DNS entry, but life is rarely that easy.
Obviously, this sort of procedure takes some time to work out and to test, so if you really want to minimize downtime, you'll be spending many, many, many hours doing dry runs.
If that is still too much downtime, you generally have to resort to more application-specific solutions, which generally requires some pretty detailed understanding of the application(s) that use the database.
Justin