Re: Help required on Data Guard

spraveen2001_at_yahoo.com (Praveen) wrote in message news:<98d8ec76.0411282220.1af71b89_at_posting.google.com>...
> Hi,
>
> Sorry!!! for the late response.
>
> > Get an experienced consultant in for multimaster replication. Your
> > uptime requirements sound fairly strict, is that an arbitrary
> > management decision or is it based on actual study of business
> > requirements? Or does someone just want to know how much it would
> > cost?
>
>
> Yes, it is a management decision that, there should not be no
> downtime.
>
> Actually, We will be having totally 4 oracle servers in one location.
> Out of those 3 will be in cluster and one for Backup. In these 3
> server again, 1 will be standby server. for standby server, we are
> planning to use Data Guard with RAC. I'm bit confused how this Data
> Guard will work with RAC. As, RAC works with multiple instances with
> single database. For which oracle server in RAC we need to setup Data
> Guard configuration.
>
> Could please help me???

RAC is, as you say, for a single database. Data Guard uses log files to replicate the transactions to another database. That other database could be far away, so an extreme disaster that wipes out the entire data center wouldn't affect it (assuming you have staff available, a notable problem after 9/11). Another database could also be time delayed so if something happens to corrupt the original database, you could cut off the other database before the problem propagates.

RAC and Dataguard are separate things, but they can be used together. See http://metalink.oracle.com/metalink/plsql/ml2_documents.showFrameDocument?p_database_id=NOT&p_id=203326.1 and http://metalink.oracle.com/metalink/plsql/ml2_documents.showFrameDocument?p_database_id=NOT&p_id=275977.1 and learn to poke around on OTN and metalink to find these sorts of things.

jg

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