Re: Disaster Recovery for datawarehouse

Hirshy,

By the way, if you fumble the answer to an interview question, that is a good excuse to do some research afterward and write the interviewer a followup letter with a more complete answer.

I think the answer is that the DR plan needs to be an integral part of the initial DW design. The key is being able to provide the needed recovery. You can do nologging for some operations and increase performance, but that may compromise recoverability. In some cases, you may find that just isn't an acceptable compromise. Other times you can find acceptable alternatives. For example, if you are using a batch load with nologging for performance, maybe you can save the load file. In case of a recovery, your procedure says you recover the database, then re-apply the needed batch files.

In the early days, most DW were batch loaded daily or weekly, so the DR was designed accordingly. But increasingly today, users demand their DW to be closer to real time, so your assumptions change, and so must your design change.

I would point you to Tim Gorman's writing and web site for further ideas. He suggests designing around exchange partition. This can also give you an opportunity for a back-up point.

Dennis Williams

On 11/20/07, hrishy <hrishys_at_yahoo.co.uk> wrote:
>
> Hi Chris
>
> Thanks for responding i saw the interviewer was
> coaxing me into hints saying things like dataguard but
> i had to disagree .
>
> The reason being in datawarehouses most of the times
> operations would be nologging and dataguard would not
> help much .
>
> I mentioned that they look for storage based
> replication and ability to rerun thier ETL on the
> remote site if the primary site fails and i also said
> this would be an expensive solution but the
> interviewer kept on poking me about my DataGuard
> knowledge thats why i am curious and would like to
> know what the group thinks.
>
> regards
> Hrishy
>
>
>
>
>
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