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

Maybe not "clueless", but probably unfounded. Don't forget that there's a lot more than just binaries in an OFA $ORACLE_HOME. For example, the optional Listener log ($ORACLE_HOME/network/log/listener.log) and Oracle message files ($ORACLE_HOME/rdbms/mesg/oraus.msg). One's write, the other read and every connection causes activity in both in our environment, AFAICT. Does this require multiple ORACLE_HOMEs for us? Nah. From a quick peek, we're hitting about 100KB/s cached reads (peaks at 500KB/s) and <1KB/s on writes on our $ORACLE_HOME mount point. But it could for some, depending on the load and system setup.

My $.02,
Rich

-----Original Message-----

Sent: Wednesday, September 29, 2004 1:43 PM Subject: RE: What are the implications of having several instances on a server sharing the oracle home?

To be blunt, your boss is clueless. What kind of contention is he visualizing here?

On some of our test systems, running Windows (which some would say is madness itself) we are running over a dozen separate databases (which many would say is madness itself) with one Oracle home. A couple of our prod servers, running Windows, are supporting up to 6 separate databases from a single home. While many would claim our setup is insane, it would be for reasons other than running multiple db's from a single Oracle Home.

How many things run on the same computer using the same binaries from the OS? Is that considered contention? Let's install a separate OS for each app. If you have 3 separate Word documents open at once, would you want them to each be driven by separate installations of Word? Let's install Word into a separate directory for each document.

Ask your boss to explain exactly what kind of contention (disk? memory? cpu?) he is concerned about, and then ask him to explain the theory behind releaving that contention by using multiple Oracle Homes. Gently point up the fallacies as they surface -- as they most certainly will. With careful questioning and a bit of explanation, you might get him to talk himself into a better understanding.

Ed Stevens

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http://www.freelists.org/webpage/oracle-l Received on Wed Sep 29 2004 - 13:55:12 CDT