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Home -> Community -> Usenet -> c.d.o.server -> Re: What ramifications are there for running two Instances on one host server.
Howard, can you recommend any good papers etc. on multi-instance server administration? Sometimes additional servers or consolidation aren't options (I've been struggling for three years to bring together myriad seperate projects each of which had their own instances for no good reason that I could discern except politics and ignorance). With CPU based pricing, I would expect management would be more inclined than ever to cram everything they can on one server.
In some cases, such as incompatible application requirements, I would think it would be easier to tune seperate instances even if they are on the same server. I/O contention I can figure out but am uncertain about memory allocation, network traffic etc. Most of the tuning books in my collection (admittedly I haven't had time to dig deeply) seem to assume a monolithic operation where the DBA actually controls the configuration instead of "making do" with an inherited environment. There must be other "Balkanized" installations out there though, aren't there?
fdp
"Howard J. Rogers" wrote:
>
> "toddthom" <orclnwsgrp_at_hotmail.com> wrote in message
> news:94io0r$nru$1_at_nnrp1.deja.com...
> > Hello Generous and All-Knowing,
> >
> > I'm a jdba and I'm currently involved in building an Operational Data
> > Store and a Data Warehouse on one HPUX (11.0) N-Class server......two
> > SID's one one node. We haven't actually built it yet, but, I thought
> > Oracle's rule was a one to one relationship with regard to instance and
> > database.....wouldn't this break the rule?
>
> It would only break it if you assume that a database is the same thing as a
> node. The node is the HP Server -one physical box. The database is the
> collection of controlfiles+datafiles+redo logs that relate to your Data
> Warehouse, and the second database is the collection of
> controlfiles+datafiles+redo logs that relate to your Operational Datastore.
> Two databases, one node. Nothing wrong in that.
>
> You will have to have two Instances managing those two databases -because
> the rule about 1 instance managing 1 database is always true (even in
> Parallel Server). Two Instances, one node. Nothing wrong with that,
> either.
>
> Except... that performance on either Instance will be affected by the work
> being done on the other, and the i/o on one database will be affected by the
> i/o on the other.
>
> So whilst there's nothing "wrong" with 2 or more databases and Instances on
> one node, it's not normally recommended for performance reasons.
>
> >If not, what configuration
> > recommendations would you make with regard to resources?
> >
>
> Extremely tricky to suggest anything without knowing the loads and work
> patterns for each database/instance. The simple (simplistic) advice is to
> go buy another HP Server.
>
> Regards
> HJR
>
> > Thanks
> >
> > Todd
> > Peace
> >
> >
> >
> > Sent via Deja.com
> > http://www.deja.com/
Received on Wed Jan 24 2001 - 07:10:15 CST
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