I agree with everything Tom said. Additionally, though, you should consider two other points: 1.) A single ORACLE_HOME for multiple databases means a single point of failure for those databases. You'll need to assess the=20 risk there. 2.) A single ORACLE_HOME mean all databases get patchsets and patches applied at the same time. It also obviously means all databases need to be down for the duration of the patch or patchset rollout. -Mark -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Mercadante, Thomas F Sent: Wednesday, September 29, 2004 2:26 PM To: 'achoto@xxxxxxxxxxxx'; oracle-l@xxxxxxxxxxxxx Subject: RE: What are the implications of having several instances on a server sharing the oracle home? Ana, There are at least two things to consider. If all of your applications are home grown, then sharing one Oracle home = is appropriate. The implication here is that when you choose to migrate to = a new version of the database software, that all of these database can go = at the same time. If your application are store-bought, then you have another thing to = worry about. Typically, store-bought applications will declare capatability = with the Oracle level at different times. In this case, I would think you = would want different Oracle homes. In all cases, I have never heard of (nor *every* worry about) binary contention issues between databases. This is a new one on me. Sounds = like an old main-framer talking!! :) Good Luck! Tom Mercadante Oracle Certified Professional -----Original Message----- From: Ana Choto [mailto:achoto@xxxxxxxxxxxx]=20 Sent: Wednesday, September 29, 2004 2:13 PM To: oracle-l@xxxxxxxxxxxxx Subject: What are the implications of having several instances on a = server sharing the oracle home? 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 -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l