Re: Oracle Data Guard - Any Opinions?

"Richard" <qaz1521_at_hotmail.com> wrote in message news:bg9tkd$s5v$1$830fa7a5_at_news.demon.co.uk...
> > Also, does running the standby on a much smaller
> > >machine to provide core services in an emergency work well?
> > >
> >
> > Running the standby on a much smaller system would be a stupid idea,
> > unless you want to shut part of your user community out.
>
> Financial constraints prohibit the construction of a duplicate server. A
> smaller system
> that can provide a reduced set of core functions while the primary server
is
> being fixed
> therefore seems eminently suitable to us. From the manual, it seems that
> you can't write to
> the standby database anyway, even if you wanted to, so surely it wouldn't
> need to be as powerful as the primary if it's only dealing with read
> operations (no locking or constraint validation etc).

Not at all, when you have your disaster you switch over to the standby database and that becomes your primary. You may have a business case that says you will only do that for x days and for y% of your user population, but if the business is to function as normal you would need a normal sized server. Many cases there will be a trade off and that is fine, but those who say that the budget is limited and so smaller hardware is needed need to understand that they are trading cost for functionality and performance.

> > >3 How does licencing work? If the standby database can only be used
when
> > >the primary is unavailable, will one licence cover both servers or do
> they
> > >have to be licenced separately?
> >
> > They will have to be licensed separately. Also, you seem to think the
> > standby database isn't functioning when used as a standby. This is
> > definitely not true.
>
> Certainly it's functioning, but my understanding is that you can only read
> from a standby's target tables (you can't write to them) and you can't
> access a physical standby at all unless you stop recovery. If Oracle
demand
> a full licence for this functionality then surely they are ripping us off!

I disagree. You are getting disaster recovery *and* a seperate reporting instance if you wish. Why should this functionality not cost?

-- 
Niall Litchfield
Oracle DBA
Audit Commission UK