Re: HA Clustering with RAC

Ulf wrote:

> Hi guys,
> I'm writing my diploma thesis about Disaster Recovery. I try to differ
> types of cluster depending of the layer where they are realized.
> Here is my point of view:The aim of a cluster is, that there is an
> automatic failover of resources to the secondary site that no
> transaction is lost.This means that the OS, the database and the
> application (e.g. SAP R/3) must be active on the secondary site.
that's a high availability cluster (with failover: two machines, checking each other's health, and the other taking over when one fails) you also have load-balancing clusters (for scalability, reliability, resilience)
good book: "Load balancing servers, firewalls and caches" from Chandra Kopparapu
good site: linux-ha.org
interesting project to give you insight in the material: linux virtual server.

it's a very interesting topic, but overwhelming at the start (many complex relationships between different aspects of a computer system)

linux is ideal to experiment with such techniques.  

> Here are my questions:
> On which layer (OS,DBMS,Application) is the failover realized? Can it
> be realized on different layers?Which application does support this
> function? Or have all applications to support this function?
> Do you always need a special cluster software like HACMP?
>
> I would be glad, if you could answer my questions and give me links
> where I can read something about this.
>
> Bye
Received on Thu Mar 18 2004 - 08:12:33 CST