Re: High availability for Oracle

> I asked an Oracle representat and he said Data Guard is dealing only with
> archived redo logs ...

That is partially incorrect. Data Guard does deal with redo. As Sybrand asked, "what do you think is in the archived redo logs?" However, using *archived* redo logs is only one of the options for Data Guard. If you choose to use only archived redo logs, then you cannot have zero data loss in your Standby solution. There will always be a lag between the transactions in the online redo logs and the time that log gets archived. However, to achieve zero data loss, Data Guard forces that transactions record their entries in the online redo logs of the primary database as well as ship that information to the Standby database. If a transaction cannot write to the online redo logs *and* ship that informatio to the Standby database, then that transaction cannot complete. Obviously this can introduce some performance issues, but that is the price to pay for zero data loss.

HTH,
Brian

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Brian Peasland
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