Re: Oracle Data Guard - Any Opinions?

Hi Richard,

Comments in there somewhere ...

"Richard" <qaz1521_at_hotmail.com> wrote in message news:bg90ml$dh1$1$8302bc10_at_news.demon.co.uk...
> I've been considering using Oracle Data Guard to provide disaster recovery
> for a number of Oracle 9 databases. The documentation makes it look quite
> promising but I'm seeking unbiased opinions from users who have experience
> of the product. In particular: -
>
> 1 Is it reliable? I've had disappointing experiences with Oracle software
> before.

Overall, I would say yes. We currently use Data Guard with 9.2.0.3 on Tru64 and it works well.

The only issue of note we've experienced were issues with LGWR unable to cope during peak periods causing the online redo logs to be in an "unknown" state. This was caused by a bug in 9.2.0.1, fixed in 9.2.0.3. Fix was to bounce the database and use ARCH process instead.

The ability to perform a "graceful" switchover (easily) is a brill feature, which we've used on a couple of occasions. Simplifies the whole process no end.

>
> 2 How much flexibility do you have in the choice of operating
> system/hardware/oracle version? The documentation seems a bit vague on
> this. I understand the operating system needs to be from the same
> manufacturer, solaris -> solaris, Linux -> Linux and so on but how close
do
> the versions have to be? Also, does running the standby on a much smaller
> machine to provide core services in an emergency work well?

We use identical O/S versions although the standby is on a much smaller machine. We run "core" functionality only if/when on standby site which is an accepted business decision.

>
> 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?
>

I've managed to avoid licensing issues all my life so I'm no expert here. I believe there's a separate licensing arrangement but note that the standby site can still be used (as say a reporting DB) in conjunction with the Primary database.

Cheers

Richard Received on Thu Jul 31 2003 - 08:44:42 CDT