Re: Options for wide-area database?

Dusan,

you are absolutely right that those stretch clusters are working. My point is that I think the investments you have to make in bandwidth are not reasonable. Database log shipping can be performed e.g. with a 400 GB SAP database with only 2-4 MBit bandwidth. I don't have numbers for stretch clusters but I think the bandwidth is significant higher.

pagesflames_at_usa.net (Dusan Bolek) wrote in message news:<1e8276d6.0402170732.714327a6_at_posting.google.com>...
> bandar_at_gmx.net (bandar) wrote in message news:<e623b4e7.0402161352.18048051_at_posting.google.com>...
>
> 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.
> 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.
>
> 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 - 12:34:30 CST