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Platform + version migration, no downtime?

From: Rick Denoire <>
Date: Tue, 06 Jan 2004 23:45:12 +0100
Message-ID: <>


I am in the process of migration of two databases. The first one went from Oracle 8.1.7 to on the same host (Sun-Solaris). That was done successfully via export/import, but it took 3 to 4 days to finish (including testing, adapting backup scripts etc.).

The second one is going from Oracle 8.1.7/Sun:Solaris 7 to; it is about ten times larger than the first one. In this case, using a similar procedure would take ten days at least (don't forget the network bottleneck). That is way too long. I am forced to reexamine my transition plan and need some breaking ideas.

I am wondering if it is possible to do the transition in parts, one schema at a time, without disturbing normal work. But setting up a DB link for moved schemas does not seem to be a solution because too many scripts would have to be changed and tested; something would break. I am not aware of any other "trick" to implement a distributed DB.

Another solution would be perhaps to try to upgrade the source DB from 8.1.7 to in place on the same host first, using the migration procedure to avoid time consuming exp/imp. In a second step, a replication between the two platforms (Sun and Linux) would be setup and let run smoothly until replication is complete, while work keeps going in the source DB; finally, only switching to the new platform by a simple tnsname change would be necessary.

Doing migration in place is a little bit risky, so I think that I would need a cold backup first, adding 10 hours to the procedure.

But the crucial question here is if it is possible to do an online replication of databases of the same Oracle version but on different platforms... Is there something like a logical replication? I think I have heard something similar. Not blocks are transferred, but redolog entries (I think). I don't know if "replication" is the right word. "Shadow database"? "Stand by database"?

If you wish to continue my brainstorming session, you are welcome!

Rick Denoire Received on Tue Jan 06 2004 - 16:45:12 CST

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