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Mark Bole wrote:
> Billy wrote: >
> > My point was that it's not a straight line relationship, as you claimed. > 15 1GB temp tablespaces do not take up 15 times the disk space of a > single 15GB temp tablespace. 15 100MB SGA's do not take up 15 times the > memory of a single 1.5GB SGA. 15 services in the listener do not > automatically require 15 time the network bandwidth of a single service. > > As I stated up front, I don't recommend 15 instances on a single server. > We seem to agree on this. > > But it can be done, and if done reasonably, it does not incur 15 times > the administrative and hardware overhead. This is where we disagree. > > Your statement in all caps is easy to disprove with a counter-example. > Let's say I have a server with a database used for QA and user > acceptance testing of an application prior to final release (not R&D). > For business reasons, this server is also a secondary disaster recovery > location, and as such has a physical standby database running. (Note I > said "secondary" -- as in, Murphy has taken out both my primary and my > dedicated standby). > > Your final paragraph says it all. I'm not trying to provide "bs [...] > to prop up the argument for having multiple instances". Even you > acknowledge there are exceptions to your own "inviolate" rule. I'm > (spending too much effort) quibbling over the way you make your point > (exclusively in terms of scalability), not the point itself. > > -Mark Bole
Methinks you may be missing the point. Do you need 15 servers for 15 instances at one instance per server? Paying 15X the license cost to Oracle?
Do you need 15 instances with their own SGA, data dictionary, backups, patches, etc. on a single server? Sharing the Oracle licenses.
Or do you need 15 schemas in a single database, each in its own tablespace but sharing a common SGA, common catalog, common control files, common redo logs, common backup, etc. Also sharing the Oracle licenses.
There are three possibilities ... not two. And I would prefer the third unless there is a compelling reason as to why the different applications can not co-exist.
-- Daniel A. Morgan http://www.psoug.org damorgan_at_x.washington.edu (replace x with u to respond)Received on Wed Jun 01 2005 - 16:28:06 CDT