Living replicas

Considering the possibility to maintain a total or partial copy of a database' objects in sync with another source database, I came accross different possibilities offered by Oracle. I would mention:

Stand-By database	(this is for disaster recovery only)
Advanced Replication	(different platforms + Oracle Versions)
Data Guard		(modern Stand-By)
Oracle Failsafe		(this I didn't read, does not apply)
Oracle Streams		(most feature reach, flexible way)
RAC			(instance redundance, not data redundance)

I went through a lot of docu about these topics. I think I got the essentials, but it is hard at times. The documentation seems to be written by guys not knowing about the rest of Oracle. I feel that the style and structure of the docu might be strongly improved. It takes some time until elementary features are recognized among lots of details mixed with conceptual self-admiring descriptions.

Anyway, the purpose was to find a way to migrate a "big" database (250 GB) to a different platform (disparate hardware and OS) while minimizing down time, i.e., transfer the data while the original database is still in use and switch as soon as they get in sync (exp/imp would take too long). Advanced Replication came quite close to it, but it seems to have lots of quirks. Then I "discovered" the Streams feature, quite impressive if it really works. By the way, it is available from 9.2.0.3 and later on only. That is why I will have to upgrade the source from 8.1.7 to 9.2.0.4 in-place first, then setup Streams from Solaris to Linux.

I am afraid of the gotchas and would like to hear if anyone here has gathered any experience with Oracle Streams.

Thanks a lot

Rick Denoire Received on Mon Jan 12 2004 - 17:35:53 CST