Hello NiallOf course there may be issues that do not allow for this solution. This is true for every general idea.
I just want to point that there is no bi-directional replication. First the application works on server1 and replicate to server 2. Then the application works on server 2 and replicate to server 1.The idea of building bi-directional replication is that is helps to return to the original server.
Adar Yechiel Rechovot, Israel Niall Litchfield wrote:
I guess some of the cynicism comes from the following issues that might bite such an approach. 1) Unsupported datatypes. 2) Schemas that can't do bi-directional replication - for example Oracle Apps/PeopleSoft etc 3) apps where reconfiguring database location takes more than 'just a few minutes'. Using bi-directional replication to reduce downtime is a pretty nice idea, but somewhat complex in practice and subject to all sorts of customer specific caveats.On Thu, Nov 27, 2008 at 11:50 AM, Yechiel Adar <adar666@xxxxxxxxxxxx <mailto:adar666@xxxxxxxxxxxx>> wrote:He is one of the most respected guys in the Israel oracle community. Adar Yechiel Rechovot, Israel LS Cheng wrote:Was the lecturer a pure lecturer or lecturer/consultant? Academic stuffs sounds very good always but us we live in real worlds and work with real applications. Regards -- LSC On Tue, Nov 25, 2008 at 5:05 PM, Yechiel Adar <adar666@xxxxxxxxxxxx <mailto:adar666@xxxxxxxxxxxx>> wrote: I was in a stream class today and the lecturer mentioned just this thing. Create a second database and create bi-directional streams between the two. 1) bring the application down for a minute or two. 2) change the application to access the second server. 3) bring down the first database. 4) bring up the application. It will start to put updates in the queues in the second database. 5) upgrade the first database. 6) bring up the first database and wait for the apply process to catch up. 7) bring down the application for a minute or two. 8) point the application to the first database. 9) start up the application. Upgrade completed with only a few minutes down time. Need EE for streams and works best in 10.2.0.4 <http://10.2.0.4/>. Adar Yechiel Rechovot, Israel Martin Berger wrote:Hi Keith, I have to second Carels and Michaels meanings. Your desire is highly complex and multi dimensional. So you will not get any straight forward answer. In one of my prior lives I had to promote and support Multi Master Replication. If someone uses this wise, he canachieve a zero-downtime environment. But be warned: You need a tremendous engineering work andstill really good skilled operational DBAs with enough time to take care of. I have never checked, wether or not streams can provide the same functionality. Maybe it's worth checking. just some ideas, might they help, Martin -- Martin Berger http://berxblog.blogspot.com<http://berxblog.blogspot.com/>Hi, I'm working with a customer running a critical web site on a 10gR2 RAC backend DB - they support hundreds of thousands of simultaneous connections at the "quietest"time. They have expressed a desire for NO downtime during ANYchanges to Oracle, particularly the application of Oraclepatches and Oracle upgrades (both minor and major), etc. Any thoughts? Who's "been there done that"?-- Niall Litchfield Oracle DBA http://www.orawin.info
