Re: What ramifications are there for running two Instances on one host server.

My own 2 cents -
The reason companies often won't let all the managers on the same project fly together, and the reason the US Olympic figure skating team is not allowed on the same plane since the 1961 crash, is because in these situations - if something should go wrong, a lot goes wrong. This may seem a little melodramatic, but it is the same principle with running instances on the same box. If you have two mission critical DB instances on the same box, one could possible affect the other. So, for development, running multiple instances on the same box is pretty common, for production, less so. Running development and production on the same instance is a no-no, because a developer can do something horrible with some bizarro run-away query that affects production, and vice versa. (That isn't a real good example, but you can use your imagination).. In my ideal world, production instances should be on their own box, but it isn't always so. $$$ comes into play. Sometimes it appears somewhat cheaper to run a couple of different production apps on one big box, then break them into 2 smaller boxes. The argument is that 2 boxes means more time for administration etc., In this case, it becomes a risk vs. reward trade-off. Your original inclination seems to be to get more things on one box due to CPU based pricing, and other reasons that center on the administration argument. It a lot of cases, this is a great idea, but other times, not so. All depends on mission criticality v. ease of administration.

Just my opinion,
Doug

On Thu, 25 Jan 2001 07:25:03 +1100, "Howard J. Rogers" <howardjr_at_www.com> wrote:

>Hi Fred: regrettably, I can't recommend anything along those lines (though
>I'm sure someone else will be able to do so). I work in the idealised world
>of teaching people how Oracle works *in principle*, and in principle, you
>shouldn't do it!!
>
>I do sympathise, though. Oracle pricing is scary at best, and the
>temptation (and need) to skip on having multiple servers is correspondingly
>large. I suspect Jonathan Lewis might be your best source of advice on the
>potential pitfalls.
>
>Regards
>HJR
>
>
>
>
>"Fred Pierce" <fpierce_at_avialantic.com> wrote in message
>news:3A6ED437.3F6A1D4A_at_avialantic.com...
>> 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
>>
>> ---------------------------------------------------------
>> Fred Pierce (DNRC) Gee I hope nobody from work reads this...
>> www.Avialantic.com fpierce_at_avialantic.com
>> MAAM World War II Weekend Airshow June 8-10 2001
>> www.maam.org/maamwwii.html
>> World Airshow News - www.wanews.com
>> ---------------------------------------------------------
>>
>> "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 - 21:55:52 CST