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

From: <tim_at_sagelogix.com>
Date: Wed, 29 Sep 2004 12:41:53 -0600 (MDT)
Message-ID: <1645122.1096483313534.JavaMail.oracle@ocs.sagelogix.com>

Ana,
Especially if you are using the OFA standard (almost unavoidable these days, thank goodness!), then you won't have any performance or contention problems having multiple database instances sharing the same ORACLE_HOME. The OFA (a.k.a. "Optimal Flexible Architecture") standard provides, among other benefits, separation of the Oracle software distribution (i.e. ORACLE_HOME directory tree) from database files and config/trace/log/administrative files.

In the past, there were problems with some limits impose by the various distributed file-systems (i.e. Novell shared drives, etc) on some OS's (i.e. NT4.0 and prior, etc) causes failures due to file locks, but I haven't heard anything about that lately. Again, those were straight-out failures, not performance issues, anyway...

The pro's and con's of sharing ORACLE_HOME are:

Pro1=saves space
Pro2=one-stop patching (i.e. "all for one and one for all")

Con1=one-stop patching (i.e. "all for one and one for all")

1a) Oracle patching/maintenance applies to all databases, may not be desirable Con2=same OS user owns all processes

       2a) more difficult to monitor each instance from OS level
       2b) impossible to separate "ownership" of databases to different DBA teams

Some of the "cons" may or may not apply to your situation...

Hope this helps...

-Tim

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Subject: What are the implications of having several instances on a server sharing the oracle home?
To: oracle-l_at_freelists.org
Message-ID: <OF522473EB.7E932F16-ON85256F1E.0061F6DF-85256F1E.006448A3_at_american.edu> From: Ana Choto <achoto_at_american.edu>
Date: Wed, 29 Sep 2004 14:13:20 -0400
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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. Space is not an issue for him. The problem with this setting is that I will have to apply patches to all of them.

I have on a server four databases, three of them share the binaries, they are on 9iR2, and I also have a 10G instance on its own oracle home. The 9i DBs are not heavily used so I can't tell if there is performance issues with them. I don't see a problem with the 10G db, although no one but me is using it.

On another server I have three databases in their own oracle home. Two instances run on 8.1.7.4, one is the datawarehouse and the other one is oltp. No performance problems there. Another oltp database (9iR2) resides on the server, and I don't see any performance issues there either.

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

Thanks

Ana E. Choto
American University
e-Operations - Information Technology
Phone (202) 885-2275
Fax (202) 885-2224

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http://www.freelists.org/webpage/oracle-l Received on Wed Sep 29 2004 - 13:40:16 CDT