Generally it's bad because there is a certain level of resource consumption for an instance of any size. So pay the price ONCE and have an instance large enough to do all the work needed by all the applications using the database. There can be cases where multiple instances on the same box are needed, but many cases that I have seen it was not needed. Many times folks can use one instance (or at least fewer instances) to get the work done. Ric Van Dyke Hotsos Enterprises ----------------------- Hotsos Symposium, be there: http://www.hotsos.com/portal/events/SYM06 -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Tom Fox Sent: Thursday, March 30, 2006 12:53 PM To: David Sharples Cc: roger_xu@xxxxxxxxxxx; Oracle-L@Freelists. Org (E-mail) Subject: Re: two databases in a server I've heard the argument before about having more than one instance on a machine is a bad idea. However, on the flip side, having 50 applications share one instance can be bad, as if one app needs a particular patch, you're affecting 49 other applications due to one application's requirements. Anyone care to elaborate why more than one instance is bad? --Tom On Thu, 30 Mar 2006, David Sharples wrote: > by joining them into a single instance - that is best practise > -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l