Hi all,

I would like to have a COB (Continuation of Buisiness solution) with Oracle. In more details i need to have two databases in two different physical locations and must be consistent at the point of time failure. I know that there is a cluster solution for Oracle but i need more information in this area. If anyone could contribute a knowledge i would appreciate it a lot. Hope that is clear what i need to do as a task.

Thank you in advance

Oracle does have the stretch cluster, but no your requirement is not very clear. All clustering solutions share the storage, so they will be consistent at failure, since they are accessing the same data.

a physical standby using data guard

Let me try to be more specific on the demand, lets suppose that we have two different buildings where each of them have an identical database. How the primary database will update the secondary one? Apart from the archiving method and standby database is there any other solution more automated and robust? I need the case if one building has a natural damage then the other building with the secondary database to take the control and ofcourse has to be updated at the point of failure.

"I would like to have a COB (Continuation of Buisiness solution) with Oracle. "

You want HA, High Availability, correct?

Oracle's "cluster" solution is called RAC, but you have other choices, including n-way streams and data guard.

n-way Streams is oftern a better solution that RAC, it's very fast, and far cheaper TCO.

http://www.rampant-books.com/book_2004_2_streams.htm

"In more details i need to have two databases in two different physical locations and must be consistent at the point of time failure"

None of the tools are consistent at the point of failure, since there will alwsys be in-flight uipadres and have not been comitted. However, you can use RAC with TAC using the preconnect method.

http://www.dba-oracle.com/art_oramag_rac_taf.htm

I think HAL9000 means RAC with TAF (Transparent Application Failover) using the preconnect option.

RAC requires two or more nodes with Oracle installed, plus the data is stored on a shared storage device, normally some sort of storage array external to the Oracle servers.

It really sounds to me like you do want a RAC solution. Keep in mind that RAC however is only HA if the hardware itself is set up properly. The key item that many sites forget is the storage, that is RAC and RAID is not sufficient, the site needs to have full replication of some sort in case the storage array itself suffers some sort of catastrophe.

So, in this case not only do you need two nodes (or however many is appropriate), but you also need to duplicate your storage subsystem in case the primary is lost. If you have two physical locations, the logical solution would be to configure one for the primary storage, and replicate the drive to the other site as backup.

Below is a link to some good information about the relative prices of various Oracle availability methods.

http://www.dba-oracle.com/oracle_tips_failover_prices.htm