Re: Options for wide-area database?

> Maybe you should specified what you mean by term "distance". It is
> possible to deploy successfully stretch cluster using synchronous
> transfer to up to 40km and using asynchronous transfer up to hundreds
> or even thousands kilometers. In fact you can even deploy asynchronous
> stretch cluster on continental distance (east coast - west coast). So
> I do not see any real limitations here.

I don't think RAC can be set up with async.

> Real Application cluster can be deployed on distance let say up to 15
> kilometers. And because you were talking about problems with latency,
> I can tell you that we have achieved ms latencies with gigabit
> capacities on thirty kilometers distance. So no big deal here.

Like your experience, I believe with 100km in a metro environment is do-able because the latency is very low. But I'm thinking about RAC over hundreds to thousands of kilometers.

>
> Dusan Bolek
>
> > RAC over Wide Area Network requires block-based replication utilizing
> > your Storage Technology. I NEVER saw blockbased storage replication
> > over distances working at a satisfying degree. Storage companies
> > advertise FibreChannel over IP ... will believe that when I see it.
> >
> > I used to work for a hardware manufacturer 3 years ago. All the
> > technical people doing implementation went crazy when another sales
> > guy sold a "Metro Cluster" (in fact RAC would need a hardware cluster
> > as a basis) because it's not working (network latency)
> >
> > Consider using data guard but also consider third party products as
> > data guard is not perfect either. If the database is not to big use
> > Shareplex (heavy I/O as far as I know, usually not perfect with
> > complex SAP environments) or think about other alternatives. A product
> > called DBShadow is handling it pretty well, too.
> >
> > ... my opinion.
Received on Tue Feb 17 2004 - 14:34:49 CST