Re: RAC - Is it wise/ok/possible to run multiple databases across the same cluster?

It'll be best to run one RAC database on top of one cluster, but sometims your applications cannot share the same RAC database, I guess that's reason why OP wants to do that. I am facing the same situation in that we have 4 different ERP apps that cannot share the same RAC database. We are planning to run these 4 dbs on top of a 6-node cluster.

-Li Li
IT Engineer
OUHSC - Infrastructure Services

On 5/1/07, Job Miller <jobmiller_at_yahoo.com> wrote:
>
> what are the demands that drive the requirement for multiple databases in
> the same cluster vs. a single larger database using the resources of the
> cluster?
>
> for those that have multiples in the same cluster, does each db have its
> own shared home, are all the dbs on a particular node using the same local
> home, or does each db on each node have its own local home?
>
> I have heard cases where folks divide up nodes to form a set of smaller
> clusters, where each cluster runs a separate db. In this scenario each box
> has a single db on it (traditional best practice), and any box could be
> repurposed to join any other cluster at any time it as needed. That assumes
> you have enough boxes. If you are running 7 dbs in a 3 node cluster, it
> obviously doesn't work.
>
> Job
>
>
>
>
> *"Mark W. Farnham" <mwf_at_rsiz.com>* wrote:
>
> IF you've got the shared disks for all the databases "zoned" for access
> by all the hosts (machines) and sufficient interconnect bandwidth amongst
> the machines, then it is really just a question of gracefully starting and
> stopping the relevant instances of the databases on the various machines.
>
> Automating all this to dynamically adapt to load spikes would be one of
> the many conflicting definitions of "grid." Doing it "by hand" at predefined
> workshifts should be reasonably manageable. You **might** want to avoid
> actually shutting down the non-prime-shift instances on C & D and just make
> it impossible to open a session on them if memory is not an issue on the C &
> D hosts. That depends on issues like pre-warming the cache, "kept" lookup
> tables and packages, etc. versus the resource cost of keeping the idle
> instances up and checking them for blocks (which should approach zero cost
> as the length of idleness increases).
>
> Don't confuse my statement that it should be possible with the idea that
> this is the best architecture for a given system.
>
> Regards,
>
> mwf
>
> ------------------------------
> *From:* oracle-l-bounce_at_freelists.org [mailto:
> oracle-l-bounce_at_freelists.org] *On Behalf Of *Ethan Post
> *Sent:* Monday, April 30, 2007 3:52 PM
> *To:* Kerber, Andrew W.
> *Cc:* oracle-l
> *Subject:* Re: RAC - Is it wise/ok/possible to run multiple databases
> across the same cluster?
>
> OK, I had heard that perhaps there are issues because of the interconnect
> uses UDP. The goal would is to for example allow say 3 databases access to
> machines A & B during the day, while another database has exclusive access
> to C & D, then at night allow one of the first three databases to access A,
> B, C & D.
> On 4/30/07, *Kerber, Andrew W.* <Andrew.Kerber_at_umb.com> wrote:
> None that are different than any other requirements. You don't even have
> to cluster all the instances.
>
> -----Original Message-----
> *From:* oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org]
> *On Behalf Of *Ethan Post
> *Sent:* Monday, April 30, 2007 2:19 PM
> *To:* oracle-l
> *Subject:* RAC - Is it wise/ok/possible to run multiple databases across
> the same cluster?
>
> Are there any technical limitations in regards to running multiple
> databases across the same set of servers in the same cluster
>
>
> ------------------------------
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