Re: Logical Standby Database 10gR2

On Apr 25, 8:13 am, tinojam <tino..._at_gmail.com> wrote:
> We are designing a DR plan for our production database which is a
> Oracle10gR2 RAC database with three nodes in the cluster. Based on our
> business requirements and cost constraints we have decided to build a
> logical standby RAC database (3 nodes) at our remote site. The
> business wants to use the standby database as a DR database and for
> reporting, 24X7. That is why I went the logical standby route. I have
> done the ground work in terms of checking that there are no
> unsupported data types for the logical standby db and everything
> checks out.
>
> Now the problem is this: the DBA team went to a presentation and an
> Oracle representative told them that they need a physical standby and
> a logical standby database to ensure the logical standby database
> works. He is saying that he wouldn't recommend having a logical
> standby db by itself, you need a physical standby database, based on
> best practices.
>
> Now the DBAs want the design to be changed to accommodate both a
> logical and physical standby database... extra cost and
> administration!
>
> Is there anyone out there just using a logical standby database for
> both reporting and DR without a physical standby?
>
> I have been working with standby databases since Oracle8i and I am
> sure the design is up to par. I want to get feedback from the group on
> this...

I believe that the big issue with physical versus logical standby, in the context of DR, is simply that with logical, you cannot apply archived redo from the master, as the logical standby is not duplicated at the block level. With a physical standby you could move archived redo from the master and recover up to the last archived SCN, without any real headache.

So, afaik, logical standby is simply not viable for DR... unless you're okay with it not being up-to-date with the last log switch on the master.

Cheers,

BD Received on Thu Apr 26 2007 - 01:32:32 CDT