Re: RAC, extra nodes, load-balancing and failover

"PdV" <piet.de.visser_at_cmg.com> wrote in message news:6de2ae57.0212130043.50690481_at_posting.google.com...
> Group,
>
> We have installed OCFS and RAC on an HP-proliant cluster, on RH 21 AS.
> So far it works well, including failovers.
> It even scales surprisingly well.
>
> Aim is a large database using cheap hardware, and scalability on demand
> by adding extra nodes and instances.
> We aim for a clustered file system, want to avoid raw-devices,
> and would like software on CFS as well (single install, no replication).
>
> We control the servers, but not the client-machines, more specific:
> we cannot modify Tnsnames on app-servers or on client-machines.
>
> Question about adding extra nodes+instances to the cluster.
>
> If we add an extra node and instance (add redo-, add undo-ts, add public
thread...)
> and start the instance, say instance i3 on node n3,
> will new incoming connections be able to connect to it, and will
load-balancing
> occur over the additional node as well as over the existing nodes ?
>

Depends. What are clients connecting to at the moment? If they are connecting to a specific instance then (1) you're missing the point and (2) no. If they are connecting to the RAC service, then yes, they may well be directed to the new node, because that what Listeners do.

> The new instance will be able to register with existing and new listeners,
> but the client-machines only know about the original two nodes in their
> tnsnames.ora.
>

Then you haven't configured the tnsnames.ora correctly, and have misunderstood what RAC is all about.

> More specific :
> - will (can?) load balancing include the added nodes ?

Nope. Not given your last statement.

> - will failover work for connections to the new nodes ?
>

Who knows. Failover is a product of a correctly configured tnsnames (or equivalent) which you haven't got, and the use of OCI, which I wouldn't know about.

HJR  > nb: apologies or not reading the whole FM (for sqlnet) up front.
>
> Any thoughts ?
>
> Regards,
>
> PdV
Received on Fri Dec 13 2002 - 03:55:17 CST