Re: What are the implications of having several instances on a server sharing the oracle home?

  • From: "Nuno Pinto do Souto" <nsouto@xxxxxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Thu, 30 Sep 2004 08:19:26 +1000 (EST)

Quoting from AUTHOR Ana Choto:

> My boss thinks that this could cause problems.  I say it's OK to have,
> say three Oracle instances  (or more) sharing the binaries, as long as
> we have enough memory and space.  He thinks we should install the
> software for each instance to alleviate contention for the binaries.

He thinks wrong.  There is no such animal as "contention for
the binaries" in modern operating systems, Windows included.
Provided you stay within the requirements of OFA, you are
always fine.  But he may be right also.  Read on, please.

> Space is not an issue for him.  The problem with this setting is that I
> will have to apply patches to all of them.

Yes, that is a problem.  On the other hand, the problem with
the "shared by all" approach, as others have pointed out, is
that you cannot apply independent releases of the software to
a given subset of your databases.  That could create problems.

> Is someone out there willing to share his/her experiences with any of
> these settings?

Well, put it this way:
I think you are right and wrong.  Let me explain.
You are absolutely right in the "contention" bit: there is
no such thing nowadays.
But I think you may be wrong in sharing the same executables
with all databases.  Why?

Imagine this scenario: you receive an Oracle upgrade that will
require some changes/testing of your apps BEFORE you send it
to production.  One copy of the binaries later, you realize
that you have just upgraded ALL your Oracle databases to the new
release without first testing!

See what I mean?

I'd stick with two copies of the software.  One used for production
databases and critical user acceptance testing (if you bother
with that sort of thing - many do).  The other used for all
development databases.

And you won't ever have problems with upgrades.  And you'll STILL
be sharing executables.   And your boss will get the Charlie Brown
"pee in your dark pants" syndrome.  You know: gives him a warm
feeling and no one notices.

Win-win situation, no?  ;)

Nuno Souto


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