Re: Oracle Data Guard - Any Opinions?

> 1 Is it reliable? I've had disappointing experiences with Oracle software
> before.

Dataguard shipped with 9R2 is quite good - previously you couldn't do an 'easy' switch-over/switch
back with the gui.
Only negative thing - but that should be fixed in 10i - if you decide to use a physical standby (maximum
performance), the online redolog files are still used by ARCH to ship over to the standby DB. If you have
a low bandwith network (say 512Kbit leased line) and there's a lot of redo generation, this results in severe
performance loss of the primary DB because ARCH still has a filedescriptor open on the online redologs
which are needed to overwrite by LGWR -> hangs. The workaround is creating a huge amount of loggroups but at
some point the DB will of course come to a halt (with low bandwith networks).
There are change requests for ARCH to use the offline redologs instead of online redologs as well as
on the fly compression of redo ...

"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.
>
> 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?
>
> 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?
>
> Thanks for any advice,
>
> Richard
>
>
Received on Wed Jul 30 2003 - 14:44:29 CDT